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SKERRYVORE LIGHTHOUSE.

ACCOUNT
OF THE
SKERRYVORE LIGHTHOUSE,
WITH
NOTES ON THE ILLUMINATION OF LIGHTHOUSES;

BY
ALAN STEVENSON, LL.B., F.R.S.E., M.I.C.E.,
ENGINEER TO THE NORTHERN LIGHTHOUSE BOARD.

“ΥΠΕΡ · ΤΩΝ · ΠΛΩΙΖΟΜΕΝΩΝ”
Inscription on the Ancient Pharos of Alexandria.

BY ORDER OF THE COMMISSIONERS OF NORTHERN LIGHTHOUSES.

ADAM AND CHARLES BLACK, NORTH BRIDGE, EDINBURGH.
LONGMAN AND CO., LONDON.

MDCCCXLVIII.

PRINTED BY NEILL AND COMPANY, EDINBURGH.

PREFACE.

I am unwilling to dismiss the following pages from my hands without saying a few words in extenuation of the defects which they contain. My chief plea in defence is, that the preparation of this Account of the Skerryvore Lighthouse, and the Notes on the Illumination of Lighthouses which follow it, was not chosen or assumed by me, but was a task imposed by the express desire of the Lighthouse Board, to whose enlightened and liberal views the Mariner owes the erection of the Lighthouse itself. My labours were also continually interrupted by the urgent calls of my official duties; and, on several occasions, I was forced to dismiss unfinished chapters from my mind for a period of several months—circumstances which, I hope, will in some measure account for the desultory character of the performance, the disproportion of some of its parts, and more especially for repetitions and perhaps omissions which would otherwise have been quite unpardonable.

Having said thus much by way of apology for this Volume, I must acknowledge my many and great obligations to my Father who preceded me as Engineer to the Board of Northern Lighthouses, and of whose experience, as the Architect of no fewer than twenty-five Lighthouses, including that of the Bell Rock, I had the full benefit during the erection of the Skerryvore Lighthouse. To the generosity of my esteemed friend, M. Leonor Fresnel, I owe all that I know of the Dioptric System of Illumination, invented by his late illustrious Brother; but this general acknowledgment will not supersede the necessity of frequent repetitions of my obligations to him, as occasion offers, in the course of these pages. I have also derived much assistance, as a careful reader will easily trace, from the valuable little work of M. Peclet, entitled Traité de l’Eclairage. There are, besides, many other obligations, which I cannot attempt to acknowledge individually, but which those, who kindly conferred them, well know how much I value.

In the Account of the Skerryvore Lighthouse, which forms the first part of this Volume, there is an important omission; and, in this short prefatory notice, I gladly embrace the only opportunity, which now remains, of supplying the defect. Although, in the course of the Narrative, I have occasionally noticed some special deliverances from danger, I have altogether neglected to record the remarkable fact, that, amidst our almost daily perils, during six seasons on the Skerryvore Rock, there was no loss of either life or limb amongst us. Those who best know the nature of the service in which we were engaged,—the daily jeopardy connected with landing weighty materials in a heavy surf and transporting the workmen in boats through a boisterous sea, the risks to so many men, involved in mining the foundations of the Tower in a space so limited, and above all, the destruction, in a single night by the violence of the waves, of our temporary barrack on the Rock, which had cost the toils of a whole season, will not wonder that I am anxious to express, what I know to have been a general feeling amongst those engaged in the work—that of heartfelt thankfulness to Almighty God for merciful preservation in danger, and for the final success which terminated our arduous and protracted labours.

Edinburgh, March 25, 1848.

CONTENTS.

APPENDIX.

PLATES.

ERRATA.

PART FIRST.
ACCOUNT OF THE SKERRYVORE LIGHTHOUSE.

INTRODUCTION.

In the course of preparing the account of the building of the Skerryvore Lighthouse, it occurred to me, that a short Introduction should be prefixed, embracing a concise view of the constitution and acts of the Board of Commissioners of Northern Lights, more especially from 1824, when my Father’s work on the Bell Rock Lighthouse was published, up to the present time. This object will be best accomplished, by presenting to the reader, in the first place, an account of the constitution and powers of the Lighthouse Board, chiefly drawn from the “Introduction to the Bye-Laws, Rules, and Regulations of the Commissioners of Northern Lighthouses,” prepared by a Committee of their number; and by afterwards briefly noticing the principal works of the Board since 1824, and stating generally the nature of the changes and improvements made within that period on the mode of illumination, of which I propose, in a subsequent part of this volume, to give a somewhat detailed account.

The trade of Scotland had begun to increase very soon after the settlement of the civil war in 1745; but it was not till the year Constitution of the Lighthouse Board. 1784 that the general establishment of Sea Lights upon the Coast appears to have been brought under the notice of the Legislature. In that year, the subject was first mentioned at a meeting of the Convention of the Royal Burghs of Scotland, by Mr Dempster of Dunichen, M.P., the Provost of the burgh of Forfar; and, in the year 1786, that gentleman brought a bill into Parliament, and an Act was obtained establishing the present Board of Northern Lights.

This Act sets forth, that “it would conduce greatly to the security of navigation and the fisheries, if four Lighthouses were erected in the Northern parts of Great Britain, one on Kinnaird’s Head, Aberdeenshire, one in the North Isles of Orkney, one on the point of Scalpa, in the Island of Harris, and a fourth on the Mull of Kintyre, Argyllshire;” and it accordingly authorises the erection of those four Lighthouses. The Commissioners appointed for carrying this Act into execution were, the Lord Advocate and Solicitor-General of Scotland, the Lord Provost and first Bailie of Edinburgh, the Lord Provost and first Bailie of Glasgow, the Provosts of Aberdeen, Inverness, and Campbeltown, the Sheriffs of the counties of Edinburgh, Lanark, Renfrew, Bute, Argyll, Inverness, Ross, Orkney and Zetland, Caithness, and Aberdeen. An Act was subsequently passed, which authorised the Commissioners, when any new Lighthouse was established on any part of the coast of Scotland, to add to their number the Provost or Chief Magistrate of the nearest Royal Burgh, and also the Sheriff-Depute of the nearest county; and, by the exercise of this power of assumption, the board now includes the Sheriffs of the counties of Ayr, Fife, Forfar, Wigtown, Sutherland, Kincardine, and Kirkcudbright. To enable the Board to carry on the intended works and to provide the means of maintaining the Lights, those Acts gave power to the Commissioners to levy a duty of 1d. per ton on British vessels, and 2d. per ton on foreign vessels; and liability to pay this duty was incurred by all vessels passing any of the Lighthouses in the course of a voyage; but this single payment freed them from any farther exaction, although they should pass more than one Lighthouse in the course of the voyage. The Board held its first meeting at Edinburgh on 1st August 1786. A Secretary and Engineer were appointed, and a resolution was adopted to borrow L.1200. For this sum the Magistrates of the five Royal Burghs named in the Act interposed their security; and, at the same time, assigned, in farther security, the duties under the Act of Parliament. After appointing a Committee to prepare matters for a general meeting, they adjourned till the 23d of January 1787. Some inconvenience having been felt in conducting the business of the Board, particularly in the holding of stock and other property, by reason of its not being an incorporated body, an Act was obtained for erecting the Commissioners into a body politic, by the name of the “Commissioners of the Northern Lighthouses.” Several Acts have been subsequently passed, in order to facilitate the erection of particular Lighthouses, and for the purpose of granting duties for their support. All those duties, however, are now abolished, and others have been substituted, the collection of which is regulated by an Act, 6th and 7th William IV., cap. 79, intituled, “An Act for vesting Lighthouses, Lights, and Sea-marks on the Coasts of England, in the Corporation of Trinity-House of Deptford Strond, and for making provision respecting Lighthouses, Lights, Buoys, Beacons, and Sea-marks, and the Tolls and Duties payable in respect thereof.” This Act declares, “That from the first day of January one thousand eight hundred and thirty-seven, the tolls now payable by or in respect of vessels for or towards the maintenance of the several lighthouses at present under the management of the Commissioners of Northern Lighthouses shall cease to be payable, and that, in lieu thereof, there shall thenceforth for ever be paid to the said Commissioners of the Northern Lighthouses, for every vessel belonging to the United Kingdom of Great Britain and Ireland (the same not belonging to his Majesty, his heirs or successors, or being navigated wholly in ballast), and for every foreign vessel which, by any Act of Parliament, order in Council, convention, or treaty, shall be privileged to enter the ports of the said United Kingdom, upon paying the same duties of tonnage as are paid by British vessels (the same not being vessels navigated wholly in ballast), which shall pass any of the said lighthouses, or derive benefit thereby, the toll of one halfpenny per ton of the burden of every such vessel for each time of passing every such lighthouse, or deriving benefit thereby, and of one penny per ton for each time of passing the Bell Rock Lighthouse, and double the said tolls for every foreign vessel not so privileged.” And with regard to any new Lighthouses to be hereafter erected, it is provided, that there “shall be paid to the Commissioners by the owner, or other person having the command of any vessel not belonging to His Majesty, which shall pass such lighthouse, or derive benefit thereby, such reasonable toll as shall have been first approved in that behalf by His Majesty in Council.” Before the passing of this Act, the Commissioners had been uncontrolled in the selection of stations for Lighthouses, or in choosing the characteristic appearance for the Lights; but it being considered desirable to have a systematic arrangement in the three kingdoms, the Irish Lighthouse Board, as well as the Commissioners, are now required to give notice to the Corporation of the Trinity-House of Deptford Strond, before altering the character of any Light, or erecting any new Lighthouse; and that Corporation must, within the period of six months after receiving such notice, signify their opinion as to the propriety of the change, or the utility of any new Lighthouses submitted for their consideration. The Act, however, provides, that, if the Commissioners are dissatisfied with the opinion of the Trinity-House, they may appeal to the Privy Council, whose determination is final. By this Act, also, an important power is given to the Commissioners to control the exhibition of all harbour and local Lights, or other sea-marks, and to prevent the exhibition of any Lights or fires on the sea-coast, which might be mistaken for the regular Lights exhibited by the Board. In the Appendix I have given a copy of the [Annual Statement] of the Income and Expenditure of the Board for the year 1846, prepared by Mr Alexander Cuningham, the Secretary to the Commissioners.

Since the Sumburghhead Lighthouse in Zetland was lighted in the year Lights established since 1821. 1821, with a notice of which the account of the Bell Rock Lighthouse concludes, the Commissioners have been engaged in the establishment of seventeen new Lighthouses, and the remodelling of several old ones; and they have, more particularly, effected important changes in the mode of illumination, and have begun to place Beacons and Buoys on the coast. They have, besides, executed several considerable improvements, for the purpose of facilitating the communication with the Lighthouses at Kintyre in Argyllshire, Cape Wrath in Sutherlandshire, and Dunnethead in the county of Caithness, by the establishment of landing-piers and the formation of roads, varying in length from three to ten miles, in connection with those Stations. Of those works, many interesting details might be given, were it not desirable that the introduction to an account of a single Lighthouse should be restricted within a very moderate compass; and I have, therefore, thought it sufficient to lay before the reader the most important circumstances of each Lighthouse Station belonging to the Board in a tabular form in the Appendix.

I shall not, in this place, enter on any exposition of the general principles which regulate the illumination of Lighthouses, and still less will it be proper to discuss the advantages of the different methods of illumination by Reflection and Refraction, as I shall, in the [sequel], find a more convenient opportunity for speaking somewhat in detail on those subjects. It will be enough to present a very brief notice of the Improvements in the mode of illumination.improvements in the mode of illuminating Lighthouses, which the Northern Lights Board have introduced since 1824, up to which time, as already mentioned, a sketch of their works is already before the public. One of the most important changes in Lighthouse apparatus was, unquestionably, the introduction of Revolving Lights at the Tour de Corduan about the year 1780, by which the means of distinguishing one light from another were greatly extended, and a marked difference in the appearance of contiguous lights was at once simply obtained. The mere variation of the velocity of the revolution is so simple as to afford an obvious source of distinction among lights; and yet it is remarkable, that it was only lately that one of its principal advantages was perceived by my Father, who first applied it in the year 1827 as a means of distinction for the Light of Buchanness. This distinction consists in giving the frame a greater number of sides or faces, and a more rapid revolution, so as to cause a flash in every five seconds of time, which produces an effect so marked and characteristic as to afford by far the most effective distinction which has been exhibited since the introduction of Revolving Lights. Under the auspices of the Board, this distinction has been since applied at the Rhinns of Islay Lighthouse, and has given much satisfaction wherever it has been tried. The late King of the Netherlands, a great patron of the useful arts, was so much pleased with this device that he presented the author of it with a splendid gold medal, in token of his approbation. The only other improvement on the Reflecting Lights, which I shall notice in this place, is that called the intermittent light, which is due to the same officer, and was by him introduced at the stations of Mull of Galloway, Tarbetness, and Barrahead. It consists of the apparatus of a fixed Light, in front of which two cylindric shades are alternately shut and opened by a vertical movement, so as to produce a sudden extinction and exhibition of the light, in a manner very difference from the gradual decline and growth of the flash, which is produced in revolving Lights by the attenuating effects of divergence on the penumbral portions of the light reflected from the mirror.

Dioptric Lights. The introduction of lenticular apparatus into Lighthouses has been the last great improvement effected in their illumination. So far back as the year 1823, the attention of the Commissioners was first called by their Engineer to the invention of the late Augustin Fresnel, who had succeeded in building polyzonal lenses of large dimensions, and in adapting to them a lamp of great power, having four concentric wicks supplied with oil by a clock-work movement like that of the Carcel lamp. A committee was appointed to consider this subject; and under its direction a long train of experiments was made with those instruments and with the paraboloidal mirrors which are generally used in British Lighthouses. The results of the experiments led the Board, in the summer of 1834, to send me on a mission to France, with instructions to report my opinion as to the comparative merits of the dioptric and catoptric apparatus for the illumination of Lighthouses. Through the kindness of my friend M. Leonor Fresnel, Secretary of the Commission des Phares, who in the most liberal manner put me in possession of all the information which I required, and afforded me an opportunity of visiting the most important Lighthouses on the French coast, I was enabled on my return to report very fully my views on the various topics whose investigation had been committed to me by the Lighthouse Board.

The characteristics of the two systems of illumination by Reflection and Refraction may be briefly described as follows: In the reflecting apparatus, the lamp is placed in front of the mirror, whose surface is so formed that the rays which fall upon it, and are reflected from it, must afterwards move in lines parallel to the axis of the mirror; while in using Refracting instruments, the flame is placed behind the lens, whose action is simply to bend the rays in their passage through it, in such a manner that they come out from its face parallel to a line drawn from the focus to the centre of the lens. In Revolving Lights, on the reflecting principle, the mirrors containing the lamps are placed on a frame which revolves on its centre, and carries them round in succession to the different points of the horizon, so that each mirror produces a bright flash when it crosses the line drawn from an observer’s eye to the centre of the Lighthouse; but in Refracting Lights, a single lamp of great power is fixed in the centre of the lightroom, while the lenses, placed on a revolving frame, intercept and modify the rays which fall upon them from the Lamp, as they pass in front of it, and thus produce successive flashes whenever the centre of the lens crosses the imaginary line already noticed, as joining the observer’s eye and the lightroom.

In Fixed Lights, on the Reflecting plan, the mirrors are ranged around a fixed chandelier in tiers, one above another, their centres being placed in spiral lines, so that each shall subtend an equal arc of the horizon, and thus distribute the light with as little inequality as is consistent with the application of such an instrument as the paraboloidal mirror to this purpose. This object of distributing the light equally over the horizon, which, next to intensity, is the main object of a fixed light, and ought, indeed, to be strictly co-ordinate with it, is much better effected by using dioptric instruments. That apparatus consists of successive rings or bent prisms arranged in the form of a hoop or belt, which may be described as a cylinder, generated by the revolution of the central section of a polyzonal lens about its focus as a vertical axis, and which consequently acts only in a vertical direction, leaving the natural horizontal divergence of the light unchanged, and thus distributing it with perfect equality in every direction.

Those two systems of illumination possess advantages and defects peculiar to each. The lenticular instruments insure greater intensity when applied to revolving lights; but this advantage is in part counterbalanced by the greater duration of the flash caused by the reflectors, whose divergence is greater; while in fixed lights, the refracting instruments not only produce at least an equal intensity of light, but, what is of the greatest importance, afford the same quantity of light in all directions, a property which fixed Lights on the reflecting principle employed in Britain cannot possess.

On my return from France I made a Report, which was printed by order of the Commissioners; and the views which I gave of the superiority of the refracting apparatus, led the Board to adopt the resolution of at once converting the revolving light of Inchkeith from the catoptric to the dioptric system, as its nearness to Edinburgh offered good opportunity of observation as to the effect of the change. In October 1835, the new light was exhibited to the public, and I was forthwith instructed to make a similar change on the fixed light of the Isle of May; but in carrying this into effect, I introduced an important modification of the form of the refracting part of the apparatus, with the view of obtaining a still nearer approach to the equal distribution of the light. The only other considerable change in the lightroom apparatus which has since been effected, is the substitution of catadioptric zones in room of the mirrors hitherto used in the subsidiary parts of the larger French lights, which, as will appear in the sequel, was suggested by me in 1841, and finally carried into effect in 1843, agreeably to the computations of M. Leonor Fresnel. A Table of the Elements of those zones computed by myself, and closely verifying M. Fresnel’s results, will be found in the Appendix. The lenticular apparatus has been applied at the new Lighthouse stations of the Little Ross and the Skerryvore, and, still more recently, at Covesea Skerries, Cromarty Point, Chanonry Point, Loch Ryan, and Girdleness.

The establishment of a system of Beacons and Buoys. Beacons and Buoys on the coast of Scotland for the purpose of affording additional facilities to navigation, had long been looked upon as a desirable extension of the operations of the Northern Lights Board; and the increase of the trade and shipping of the kingdom having, some years ago, directed particular attention to the subject, a committee was named, on the 12th January 1839, to take special superintendence of that department. In 1840, the Engineer reported to the committee upwards of fifty stations for Beacons, and nearly a hundred for Buoys, as auxiliaries to the navigation in situations where the establishment of a Lighthouse was either too expensive or not warranted by the wants of the district; and means were immediately taken for erecting three Beacons in the Frith of Forth, two in the Clyde, one in Loch Ryan, and two in Cambeltown Loch. Beacons were also erected on the Iron Rock or Skervuile in the Sound of Jura, and on the Covesea Skerries in Morayshire, in connection with the Lighthouse of that name. Those works, notwithstanding many obstacles arising from doubts as to the powers of the Board, have been carried on with great vigour. In the Appendix, I have given [drawings] of three of those Beacons, one being of masonry, and the other two of iron; and also [Tables] which shew the positions of the various Beacons and Buoys at present belonging to the Board.

CHAPTER I.
TOPOGRAPHIC NOTICE OF THE SKERRYVORE ROCK.

From the great difficulty of access to the inhospitable rock of Skerryvore, which is exposed to the full fury of the Atlantic, and is surrounded by an almost perpetual surf, the erection of a Light Tower on its small and rugged surface has always been regarded as an undertaking of the most formidable kind. So discouraging was the consideration of expense, and the uncertainty of the final success of such a work, that the Commissioners of the Northern Lighthouses, after successfully completing the arduous and somewhat similar work on the Bell Rock, were induced to proceed with other operations of less magnitude, but probably, in some respects, of no less utility; and to delay the construction of the Skerryvore Lighthouse till the present time, although the Act of Parliament authorising its erection was obtained so long ago as 1814.

The cluster of Rocks, of which that called the Skerryvore is the largest, has ever been a just cause of terror to the mariner. Its dangers have long been known, and the means of removing these dangers, by converting its dark horrors into a cheering guide for the benighted mariner, have often occupied the attention of the Lighthouse Board, and especially of my predecessor in the office of their Engineer, with whom it was a constant subject of interest, from its similarity to his own work on the Bell Rock.

The first landing that my Father, in the course of his annual voyages round the coast, as Engineer of the Northern Lighthouse Board, effected on Skerryvore, was in the year 1804. In 1814, he visited it a second time, while accompanying a committee of the Commissioners on a tour of inspection to the Lighthouses all round the coast, from the Frith of Forth to the Clyde. On that occasion, Sir Walter Scott was of the party, and we find in his diary the following record of his impressions at the time, expressed in the terse and humorous language by which this interesting relic of the poet is characterised; and as the hasty observations of that great man seem worthy of a place in a work descriptive of the means which have been taken to obviate the dangers to which he refers, no apology seems necessary for introducing it in this place.

“Having crept upon deck about four in the morning,” says Sir Walter, “I find we are beating to windward off the Isle of Tyree, with the determination, on the part of Mr Stevenson, that his constituents should visit a reef of rocks called Skerry Vhor, where he thought it would be essential to have a Lighthouse. Loud remonstrances, on the part of the Commissioners, who, one and all, declare they will subscribe to his opinion, whatever it may be, rather than continue the infernal buffeting. Quiet perseverance on the part of Mr S., and great kicking, bouncing, and squabbling, upon that of the yacht, who seems to like the idea of Skerryvore as little as the Commissioners. At length, by dint of exertion, come in sight of this long ridge of rocks (chiefly under water) on which the tide breaks in a most tremendous style. There appear a few low broad rocks at one end of the reef, which is about a mile in length. These are never entirely under water, though the surf dashes over them. To go through all the forms, Hamilton, Duff,[1] and I, resolve to land upon these bare rocks, in company with Mr Stevenson. Pull through a very heavy swell with great difficulty, and approach a tremendous surf dashing over black pointed rocks. Our rowers, however, get the boat into a quiet creek between two rocks, where we contrive to land well wetted. I saw nothing remarkable in my way excepting several seals, which we might have shot, but, in the doubtful circumstances of the landing, we did not care to bring guns. We took possession of the rock in name of the Commissioners, and generously bestowed our own great names on its crags and creeks. The rock was carefully measured by Mr S. It will be a most desolate position for a Lighthouse—the Bell Rock and Eddystone a joke to it, for the nearest land is the wild island of Tyree, at fourteen miles distance. So much for the Skerry Vhor.”

[1] The Sheriffs-Depute of Lanark and Edinburgh.

Notwithstanding those occasional visits, however, it was not till the year 1834, that the Commissioners directed their Engineer to make a survey of the whole of this extensive reef, preparatory to taking measures for the erection of a Lighthouse on that part of it which might be found, after careful inspection, to afford the most suitable site; and, at the same time, the shores of part of the Island of Tyree were surveyed, with the view of establishing a Signal Tower for communicating with the Lighthouse, and of forming a small harbour, of shelter for the vessels to be employed in attending it. From these surveys the general view of the Reef which is given in [Plate II.], and the enlarged plan shewn in [Plate III.] of the Skerryvore or principal Rock, on which the Lighthouse has been built, were constructed.

The Skerryvore or principal Rock of this remarkable group, is situated in North Lat. 56° 19′ 22″, and West Long. 7° 6′ 32″.[2] It is about 11 Nautic miles W.S.W ¹⁄₄ W. of the island of Tyree, which is the nearest land, 20 miles W.N.W ³⁄₄ N. of the island of Iona, 33 miles S. ¹⁄₄ E. of the Lighthouse of Barrahead, the most southern of the Hebrides, and 53¹⁄₂ miles N.E. by N. of Mallinhead, in the county of Donegal in Ireland. It may also be added, that the principal rock is about 50 miles from the nearest point of the main land of Scotland. The extent of the Reef, and its situation in reference to the general position of the coast, will be best understood by referring to [Plate I.], which is a small Map of the British Isles. From this it will be seen that it lies in an irregular semicircular sea, inclosed by the southern extremity of the Hebrides, the rugged shores of Argyllshire, and the northern coast of Ireland on the one side, but open on the other to the Atlantic.

[2] According to information for which I am indebted to Captain Yolland, R.E., of the Ordnance Survey.

The importance of the Skerryvore as a station for a Lighthouse is so evident as to require but little comment. Although the smaller class of coasting vessels almost invariably sail through the sheltered Sounds of Mull, Loing, and Islay, to avoid the difficulties and dangers (Skerryvore among the number) of the rough navigation of the outward passage, yet these rocks lie much in the track of the larger vessels bound over seas round the North of Ireland from the Clyde and the Mersey. Government Cruisers and Ships of War are also necessarily often within a short distance of its dangers. But for homeward-bound vessels sailing for the Clyde, or for any of the Ports in the Irish sea, and directing their course for the North Irish Channel, the establishment of a light at this place is of the last importance. When such vessels happened to encounter bad weather before making land, and so had difficulty in ascertaining their true position in relation to the coast, they often, in the event of being driven so far north from their course, as to miss the lights of Ireland or that of Barrahead, continued their progress onwards in the direction of the Skerryvore Rocks; and thus, while running in apparent safety, and probably, from the state of the weather, not within sight of Tyree, which it is often difficult to see, they were very liable to encounter some of the many detached rocks and shoals which form this broken reef of nearly seven miles in extent.

In estimating the risks to which vessels were exposed from this cause, the peculiarly insidious nature of the danger must be kept in view. A headland, or line of coast, which rises to some height above the surface of the sea can be seen in most states of the weather, at a sufficient distance, even during the night, to enable the seaman to avoid danger; but, in approaching a sunken reef or a low rock, in the dark, there is no object to warn the crew of their position, until their vessel gets unexpectedly among breakers, after which it is generally too late to bring her round again. And even the very knowledge of the existence of a reef, such as this, often causes the seaman, in ignorance of its exact position, to give it too wide a berth; in which case his ship is liable to be carried away by the force of tides or winds, perhaps on a lee shore, where, although the crew may be saved, the vessel generally goes to pieces.

The exhibition of a Light, however, altogether changes the case. Instead of shunning as a danger those dreaded rocks, vessels will steer boldly on their course, until checked by the Light, availing themselves of which they will be enabled to lie off-and-on during the night, and so wait the return of daylight, in perfect confidence as to their position, and without the necessity of endeavouring to avoid hidden dangers. Thus, that which was formerly an obstruction and a danger, is rendered an aid and a safety, to the navigation of the western coasts of our country.

That this source of danger to shipping was by no means imaginary, and the consequent terror of mariners far from being ill founded, there is a too melancholy proof in the following list of disasters caused by the Skerryvore Rock, and the neighbouring dangers off the coast of Tyree:—

This list is made up chiefly from data kindly furnished to me by the Rev. Neil Maclean, the Minister of Tyree and Coll, whose long residence on the former island has afforded him ample opportunity for making observations on the subject. It is not to be imagined, however, that Mr Maclean’s list, which is made up from recollection, contains a full catalogue of the disasters caused by the Skerryvore, within the dates which it cites. Very many vessels were wrecked on this dangerous reef whose names could never be learned, and of which nothing but portions of the drift wood or cargo came ashore; and there have, no doubt, been many shipwrecks of which not a single trace has been left. Nothing, indeed, is more probable than that many of the foreign vessels whose course lay through the North Irish Channel, and whose fate has been briefly and vaguely described, as “foundered at sea,” have met their fate on the infames scopuli of the Skerryvore. It is also well known that the Tyree Fishermen were in the constant practice of visiting the Skerryvore, after gales, in quest of wrecks and their produce, in finding which they were but too often successful.

The natives of Tyree have many traditions of vessels having struck on the Skerryvore and gone to pieces; but, as might have been anticipated, few traces of this were to be found on the Rocks themselves, the breach of sea which sweeps over them during storms being sufficient to remove any heavy bodies which might be left there after a shipwreck. Some relics, however, were found during the progress of the works, and among the rest an anchor which was fished up close to the Rock, and which appeared to have belonged to a vessel of about 150 tons burden. It had been wasted to a perfect shadow by the action of the sea, and was covered with a thick coating of seaweed and barnacles. Although, however, the Rocks themselves do not retain the proofs of the disasters of which they have been the cause, the shores of the neighbouring Islands, during the progress of the works, were frequently strewed with drift wreck in such a manner as clearly to indicate what had taken place on the shoals round the Skerryvore.

On examining [Plate II.], it will be seen that what I have hitherto denominated the Skerryvore Reef, is a tract of foul ground, consisting of various small rocks, some always above the level of the sea, others covered at high water, and exposed only at low water, and others, again, constantly under the surface, but on which the sea is often seen to break after heavy gales from the westward. This cluster of rocks extends from Tyree in a south-westerly direction, leaving, however, between that island and the rock called Boinshly, the first of the great Skerryvore cluster, a passage of about five miles in breadth, and having a depth of thirteen fathoms at low water of spring tides, but not without hidden dangers, which line the rugged shores of Tyree from Kennavarah to Ben Hynish, and some of which lie farther off than might be expected. This passage is called the passage of Tyree; but it is by no means safe during strong and long continued gales, as the sea which rises between Tyree and Skerryvore, is such that no vessel can live in it. I have myself often seen it one field of white broken water, the whole way from Tyree to the Rock; and we know that the wreck of the Majestic, which occurred in 1841, during the progress of the works, was entirely caused by the heavy seas which she encountered off Boinshly.

The principal rocks of the group, are called Boinshly, Bo-rhua, and Skerryvore, while those lying to the westward, which have been more recently laid down, have received the names of Mackenzie, Fresnel, and Stevenson.

The rock called Boinshly lies about 3³⁄₄ miles from Skerryvore, and is of considerable extent. The origin of the names of the different rocks in the vicinity of Tyree is by no means clear, and very little assistance or information is to be obtained in this matter from the natives. The name of Boinshly is probably derived from the Gaelic words boun, signifying bottom, and slighe, deceitful, as indicative of the dangers of the place; but other interpretations have been put on it, and that which has been now given is by no means certain. In the course of the survey, several soundings were at considerable risk obtained, both upon this Rock itself, and in its immediate vicinity. The sea in that exposed situation is seldom so tranquil as to warrant an attempt to approach very near this Rock. The swell, which, in a greater or less degree, almost constantly prevails, is apt to impel, or seemingly draw the boat as by a kind of suction, upon the rock; and sometimes such accidents cannot be prevented, even although the greatest caution is used. Sudden lifts of the sea, during an apparent calm, are common in all the more exposed parts of the coast, more especially in the Orkney and Zetland Isles, and on the shores of the most western of the Hebrides; and any one much accustomed to the use of boats on these shores, must have experienced the hazard of encountering such unexpected risings of the sea, more especially near shelving rocks, or in rapid tide-ways. In some places the boatmen apply the name of lumps to these sudden waves. This effect is not felt to the same extent in attempting to reach a rock which is partially uncovered at low water, as a landing can, in such a case, often be effected on one side, at a time when the same rock on the opposite side, or a sunk rock just topping with the water, would, on every side, be quite unapproachable. From the soundings marked on the plan, it will be seen that shoal water extends all round Boinshly to distances varying from a quarter to half a mile. The sea breaks on the rock with great violence, and its position can easily be discovered from the island of Tyree by the white foam with which it is almost constantly surrounded, and which, in the heavy swells which sometimes accompany a dead calm, before or after a heavy gale of wind, rises to a prodigious height in a column or jet, resembling, at a distance, the play of a gigantic fountain. So high, indeed, does the sea rise on this shoal after heavy gales, that it often quite obscures the larger and more distant object of the Rock and Tower of the Skerryvore, even when viewed from the top of Ben Hynish in Tyree. The wooden barrack erected on the Skerryvore for the use of the workmen during the progress of the operations, although about sixty feet in height, was often lost sight of at Tyree by the uprising of the sea on Boinshly, and could be seen only during the calm that intervenes between returning waves.

The next Rock that occurs is Bo-rhua, a name derived from the Celtic, and signifying, according to the natives, Red Rock. It lies about 2³⁄₄ miles from Boinshly, and about one mile from the Skerryvore. The passage between it and Boinshly is clear, and has a depth of about fourteen fathoms; but it is too narrow to be safely navigated except by daylight, even under the most favourable circumstances, and then no mariner would run the risk of taking such a passage, but would prefer, even at some sacrifice of time, the fairway of the passage of Tyree. Bo-rhua is completely covered at high, but is dry at low water. The extent of rock uncovered is about forty feet by twenty feet, and the highest point of it is about six feet above low water level of spring tides. A small outlying pinnacle, about ten feet square, is also uncovered at low water. The depth immediately round Bo-rhua is considerable, from three to seven fathoms being found within fifty feet of it; and in this respect it differs from Boinshly, which, as already mentioned, is surrounded by shoal water for some distance. Between Bo-rhua and Skerryvore, however, which is a distance of about a mile, there cannot properly be said to be any clear navigable channel, as will be distinctly seen by referring to the plan. The whole of this tract may, in fact, be termed foul ground.

The Skerryvore or chief rock, and the detached rocks immediately surrounding it, were surveyed with greater minuteness than the others, as it was at once apparent, that on this part of the reef alone could a suitable site for a lighthouse be found. The name is derived from the Gaelic, and signifies the Great Rock. It is very much wasted and cut up; the number of detached rocks, sunk and exposed, in its immediate neighbourhood, whose positions were determined during the survey, amounting to no fewer than 130. The depth of water between those different detached fragments, which extend over a surface of about a mile in length, by half a mile in breadth, is considerable, varying from 2¹⁄₂ to 8¹⁄₂ fathoms at low water of spring tides.

The surface of the main or principal rock, on which the Lighthouse has been placed, measures, at the lowest tides, about 280 feet square. It is extremely irregular, and is intersected by many gullies or fissures, of considerable breadth, and of unlooked for depth, and which leave it solid only to the extent of 160 feet by 70 feet. The extremity of one of these gullies, at the south-east corner of the rock, forms the landing-creek, which is a narrow track of 30 feet wide, having deep water; and, with the help of some artificial clearing and dressing, which was executed with much difficulty, by blasting under water, while the other works were in progress, its sides and bottom are now comparatively smooth. At this place a landing can often be effected when the rock is unapproachable from any other quarter, although great inconvenience is felt from the surge, which finds its way from the opposite side of the rock, through the westward opening of the gulley in which the landing-place is situated.

Another of the gullies, immediately to the south-east of the Lighthouse, was found, on examination, to undermine the rock to the extent of eight or ten feet, and to terminate in a hollow submarine chamber, which threw up a spout or jet of water about twenty feet high, resembling in appearance the Geyser of Iceland, and accompanied by a loud sound like the snorting of some sea monster. The effect of this marine jet d’eau was at times extremely beautiful, the water being so much broken as to form a snow-white and opaque pillar, surrounded by a fine vapour, in which, during sunshine, beautiful rainbows were observed. But its beauties by no means reconciled us to the inconvenience and discomfort it occasioned, by drenching us whenever our work carried us near it. One calm day I contrived, at a very low tide, by means of ropes and a ladder, to explore the interior of the cavern, from which this fountain rose, and found it to terminate in a polished spherical chamber, about seven feet in diameter, its floor filled with boulders, whose incessant play had hollowed it out of the veined rock, and rendered its interior beautifully smooth and glassy. As I considered that this curious cavern penetrated too far, and came too close to what I had selected as the best foundation, I changed the site of the tower, so as to avoid any chance of its being undermined. I also deemed it prudent to fill up the cavity, to prevent its further extension, and at the same time to rid ourselves of the discomfort of being drenched by the column of water which spouted up from it, even during fine weather, when the sea was apparently calm. This gulley affords a good example of the power of pebbles kept constantly in play by the waves to wear down the hardest rock, and shews what extensive effects so insignificant an agent may effect in the course of time.

Before the excavation for the foundation of the tower was made, a single conical loaf of rock, about five feet in diameter, rose to the height of eighteen feet above the level of high water, the greater part of the rest of its surface being about six feet above the tide mark.

In addition to its shattered and disjointed appearance, the Skerryvore Rock presents, in another respect, a striking example of the action of the sea, which no one, on first landing on the rock, can fail to perceive. I allude to the glassy smoothness of its surface, a feature that existed to so remarkable an extent as to have proved throughout the whole duration of the work, but more especially at its commencement, a serious obstacle and hindrance to the operations. It may, at first sight, appear strange that this grievance should have been so much felt; but, when I mention that the landings were often made in very bad weather, it will be obvious that there was considerable danger in springing ashore from a boat in a heavy surf upon an irregular mass of rock as smooth and slippery as ice. The workmen were, in that respect, often sorely tried, and many inconvenient accidents occurred from falls. It was after one of these trials of patience, that the foreman of the masons was heard very graphically to describe a landing on the rock as “like climbing up the side of a bottle.” Instead of a weather-beaten rock, whitened by the dung of sea-fowls, and with marine crustacea adhering to it, the surface of the Skerryvore is smoothly polished by the action of the waves, every projecting angle or point is worn down, and the whole presents more the appearance of a mass of dark-coloured glass than a reef of gneiss-rock. Excepting in some of the more sheltered crevices, no marine crustacea find shelter; but different kinds of sea-plants grow upon it, in great abundance, at and below the low water mark. These plants are, doubtless, enabled to resist the action of the waves in the same way as the sapling, yielding to the blast, is preserved during the storm that uproots the aged and more stubborn oak.

The rocks of Skerryvore have the same characteristics as those of the neighbourhood of Tyree, being what we may, perhaps, call a syenitic gneiss, as it consists of quartz, felspar, hornblende, and also mica. It will be seen, from the narrative of the progress of the works, that this rock was, from its hardness, exceedingly difficult and tedious to excavate. The only variation in the geology of the Skerryvore, is the presence of a trap rock, in the form of a dyke of basalt, which intersects the strata, and exhibits a fine specimen of the intrusion of igneous rocks. It is shewn in [Plate, No. III.], by a thick black line.

Connected with this general view of the appearance and geology of the rock, it may be interesting also to notice, that a considerable mass of foreign matter, somewhat resembling, in its structure, a deposit of lime, was found in different places resting in horizontal layers of various thickness and size. This substance was found in pools or sheltered parts of the rock, about the level of high water mark, and, in some cases, even a little below it. It was so hard as to admit of a pretty high degree of polish; and emitted an offensive odour on being burned in the fire, or rubbed on a stone with water. It gave other clear indications of containing animal matter, and in other respects resembled the bergmeal and guano. To account for its presence in such a situation, seems rather a difficult problem. On sending a specimen of this material to my friend the Rev. Dr Fleming, Professor of Natural Philosophy in King’s College, Aberdeen, I received from him an analysis of the substance, and a concurrence in the opinion I had formed as to its containing animal matter; and Dr Fleming, indeed, expressed his belief that the matter in question is the indurated soil of birds, and had been deposited when the reef was more extensive, and the resort, and probably the breeding-place of sea-fowls.[3] How this singular formation should be found on the verge of the ocean, and even within the high water mark, in spite of winds and waves, or how it should have assumed the stratified structure which seems to indicate the depositation of successive layers in still water, are matters very difficult to be explained, without coming to the conclusion, that the uncovered surface of Skerryvore Rock must at some distant period have been much more extensive than at present, so as to permit the deposit to go on in an interior basin or lagoon, sheltered from the waves, and somewhat similar to those which Dr Darwin has described as characteristic of the Coral Isles of the Pacific. This supposition seems not at all improbable, as it does not require a great stretch of fancy to conceive, that at some period, the whole of the rocks in the immediate vicinity of Skerryvore, and extending perhaps even so far as Bo-rhua, may have been connected by a matrix of softer materials, which have gradually yielded to the action of the sea, leaving the harder portions to be smoothed and polished by the waves, and to assume the characteristic features of permanent rocks and sunk reefs which they now possess. There is also some countenance to such a view to be derived from the features of the neighbouring Island of Tyree, which contains numerous small lagoons, in which such deposits might be formed by the flocks of sea fowl which frequent them. Some of these pools are so near the shore, as to make it no difficult matter to conceive that their walls might be broken by the sea, and that they might eventually become part of it, and thus exhibit the phenomenon of deposits apparently lacustrine within the verge of the ocean.

[3] Dr Fleming has since obtained from Ichaboe indurated bird-soil or guano, closely resembling that from the Skerryvore.

Another remarkable feature which I observed in the Skerryvore Rock, was a deposit of gravel in the narrow crevices of the rock, which run nearly from north-east to south-west, dipping at an angle of 80° to the westward. In almost all of the fissures we found great quantities of small water worn boulders, less in size than a horsebean, and generally of the same materials as the rock itself. The boulders bore the appearance of having been forced into the fissures of the rock by some very powerful pressure, and were wedged hard into the crevices. In some cases a considerable quantity of softer matter containing iron was found, and in it the pebbles were imbedded. In the upper parts of the rock the crevices swarmed with centipedes of a reddish-brown colour. The rock was covered with sea fowl when first visited, and during heavy gales seals resorted to it.

About three miles to the westward of Skerryvore lie Mackenzie’s Rock, Fresnel’s Rock, and Stevenson’s Rock, which, as will be seen from [Plate II.], are connected by a tract of foul ground of about a mile and a quarter in length. Those rocks are the western limit of what we have already denominated the Skerryvore Reef. The passage between them and the Skerryvore or main rock is clear, and has a depth of water varying from eleven to twenty-eight fathoms.

Mackenzie’s Rock, which derives its name from the celebrated Marine Surveyor, is uncovered, at low water, to the extent of about forty yards, and consists of scattered patches of rock, one of which, at its highest part, rises about ten feet above high water mark of spring-tides. Fresnel’s and Stevenson’s Rocks are always under water; but the sea is often seen to break violently over them, as well as over the whole stretch of the sunken reefs which extend between them. The first of those rocks is indebted for its name to the great optical philosopher, who so greatly improved lighthouses; and the second bears the name of the surveyor who first laid down the rock,—the late Engineer of the Northern Lights Board.

During the progress of the survey, a register of the rise and fall of the tides was regularly kept at Hynish on the neighbouring Island of Tyree; and from those observations it was determined, that the rise at that place is between twelve and thirteen feet at high spring tides, and three feet at dead low neap tides; and observations subsequently made while the works were in progress, gave the same results at the Rock of Skerryvore. It is high water at the Rock at full and change of the moon, at five hours and twenty-five minutes. The tides round the Skerryvore are not remarkable for their rapidity. In spring-tides the velocity is between four and five miles, and in neap-tides between two and three miles an hour. The flood sets to the N.N.E., and the ebb to the S.S.W.

CHAPTER II.
PRELIMINARY ARRANGEMENTS AND WORKS, INCLUDING SURVEY OF THE ROCKS, AND OPENING OF QUARRIES, FROM 1834 to 1837.

In this chapter I shall very briefly notice those preliminary arrangements which may be said to have been in a great measure preparatory to the commencement of the work itself. It has been already stated, that the erection of the Lighthouse was provided for in the Act of 1814; but so formidable did this work appear, that although it was repeatedly under consideration, it was not until the General Meeting of the Board, on the 8th July 1834, that any measures were taken to carry into effect the provisions of the Act. On that occasion it was moved by the late Mr Maconochie, Sheriff of Orkney and Zetland, that the Engineer should be instructed to make the Survey of the Skerryvore Rocks. necessary survey, and to report as to the expense of erecting the Lighthouse. In terms of this remit, the survey of the Rocks was commenced in the autumn of 1834; but from the broken state of the weather, little was effected at that time beyond making the triangulation; and it was not until the summer of 1835 that the survey was completed from which the Chart, [Plate No. II.] was constructed. This survey was attended with much more labour than its extent would lead one to suppose, in consequence of its embracing the entire range of operations required in a more extensive nautical survey, and combining with the ordinary details required for a Chart, the minute accuracy in regard to surface and levels, which are always necessary for the purposes of the Engineer.

The first step was the measurement of a base line in the low lands of the adjoining Island of Tyree, which, owing to the distance and disadvantageous position of that island, could not be satisfactorily extended to the Rock without fixing stations in some of the more distant islands; and in the course of the work not fewer than twenty land triangles were measured. The calculations of the distances founded on this triangulation agreed with those afterwards obtained from the data of the Trigonometrical Survey, which were kindly furnished to me by Captain Yolland of the Royal Engineers, in 1843. For the purpose of making the soundings and laying down the sunken rocks, an entirely separate triangulation, based upon and connected with that which has already been noticed, became necessary, as the land objects were too distant, and their relative positions were such as to render it difficult by observations from them alone to determine any stations on the sea. Buoys were therefore moored at convenient points, and their positions determined by a subsidiary triangulation, so as to form a net-work of triangles between the shore and the Skerryvore Rock. The distances between these buoys were afterwards used as the bases of imaginary triangles, having points of sounding or shoals in their apex; and the angles subtended by those distances being measured by the sextant, the positions of the shoals or soundings were thence easily deduced and protracted on the [Chart].[4] In connection also with the soundings whose positions were determined in the way above described, a complete set of tide observations was made, extending over a period of about six weeks. Those tide observations were connected in point of time, with the soundings, and were employed as the means of correcting the observed depths taken with the sounding-line, so as to give the true depth in reference to the high or low water of a given tide. Accurate measurements, and minute sections, were also made of the rocks in reference to the tide-level, and more especially of the main rock, on which alone it was obvious, from the first inspection, that the Lighthouse Tower could be erected. In the course of this survey, the positions of upwards of 140 rocks were determined, and laid down on the [Chart], and 500 soundings were taken, and their positions protracted. An interesting fact was also noticed regarding the mean level of all the tides which had been watched during the period of about six weeks, as above noticed, viz., that the point half way between the high and low water of every tide is on one and the same level. This fact regarding the tides was, it is believed, first detected by my Father, in the course of some tidal observations which he made in the Dornoch Frith in 1830, and has since been observed in the Frith of Forth in 1833, and again on the shores of the Isle of Man, and at Liverpool. The agreement of so many observations by various persons at places on the opposite shores of the Kingdom, seems to imply the universality of this phenomenon in the British Seas; and the position of Skerryvore would lead to the belief, that it is not confined to narrow seas, but that it exists in the ocean. I cannot dismiss the subject of the survey, without mentioning the late Mr James Ritson, who acted as principal assistant surveyor, and to whose zeal and intelligence so much of its accuracy is to be attributed. The deep gulley which intersects the main Rock from N.E. to S.W., and across which he one day sprang while it was filled with a breaking wave, bears his name, as a memorial of his activity and perseverance. At the close of the survey in 1835, the station-pole was left wedged and batted into one of the fissures or crevices of the Rock, and a cask of water was firmly lashed to ring-bolts in a cleft of the highest part of the Rock, in the hope that it might possibly prove useful to some shipwrecked seamen.

[4] Vide Stevenson’s Marine Surveying and Hydrometry. Edinburgh, 1842, p. 144.

For the purposes of navigation generally, a survey merely indicating the position and extent of the foul ground would have been sufficient. But in connection with the work which was about to be commenced, it was particularly desirable to have exact details of the depths, rocks, and shallows of the surrounding sea, with the nature of the bottom, accurately laid down; and our experience during the course of the work, more than once shewed how essential was the possession of minute topographic information to the safety of the shipping attending the works; more especially as some of the vessels lay very near the rocks, and were frequently driven, by a sudden change of wind, to seek shelter, during the darkest nights, among the neighbouring islands.

Until this time the greatest ignorance prevailed amongst seamen as to the extent of the Reef, which had never before been minutely surveyed. Of this some proofs occurred even during the progress of the survey; for several vessels came so near the Rocks as to cause, in the minds of the surveyors, who witnessed their temerity, serious fears for their safety. On one occasion, in particular, a large vessel belonging to Yarmouth, with a cargo of timber, was actually boarded between Mackenzie’s Rock and the main Rock of Skerryvore by the surveyors, who warned the master of his danger in having so nearly approached these rocks, of the existence of which his chart gave no indication. On another occasion, a vessel belonging to Newcastle was boarded while passing between Bo-Rhua and the main Rock; and so little, indeed, had the master (whose chart terminated with the main Rock, and shewed nothing of Bo-Rhua) been dreaming of danger, or fancying that he was within a cable’s length of the reef, that he was found lying at ease on the companion, enjoying his pipe, with his wife sitting beside him knitting stockings.

Much preliminary investigation was necessarily occasioned by the difficulties and disadvantages arising from the remote situation of the island in which a great part of the works was to be carried on. Not only is the Rock itself often inaccessible and dangerous, being surrounded by numerous shoals, and visited by the heaviest seas of the Atlantic; but what gave rise to no small part of the difficulties which attended this work, was the nature of the neighbouring Island of Tyree. Disadvantages of Tyree. This island is unhappily destitute of any shelter for shipping, a fact which was noticed as a hinderance to its improvement, upwards of 140 years ago, by Martin, in his well-known description of the Western Islands.[5] Nor is its interior more attractive; for although some parts of the soil when cultivated are excellent, the greater part of its surface is composed of sand. It was therefore obvious, at a glance, that Tyree was one of those places to which every thing must be brought; and this is not much to be wondered at, as the population, who, on a surface not exceeding 27 square miles, amounted in 1841 to 4687 souls, labour under all the disadvantages of remoteness from markets, inaccessible shores and stormy seas, and the oft-recurring toil of seeking fuel (of which Tyree itself is destitute) from the Island of Mull, nearly 30 miles distant, through a stormy sea. It is said that this total absence of fuel in Tyree is the result of the reckless manner in which it was wasted, in former days, in the preparation of whisky; but, however this may be, certain it is that the want of fuel greatly depresses the condition of the people. For our works, therefore, craftsmen of every sort were to be transported, houses were to be built for their reception, provisions and fuel were to be imported, and tools and implements of every kind were to be made.

[5] A Description of the Western Islands of Scotland, &c., by M. Martin, Gent. London, 1703. Vide 2d Edition of 1716, p. 267.

In the course of the survey, much attention had been bestowed upon the selection of a convenient place for a workyard in Tyree for the preparation of materials, and in examining its rugged shores in quest of the best site for a Harbour, for the shipment of the building materials for the Rock, and for the all-important purpose of enabling the future attending vessel to lie in safety within sight of signals from the Rock, when the Light should come to be exhibited to the public. The point chosen for this establishment was Pier and workyard at Hynish Tyree. Hynish, which, though twelve miles distant, is, nevertheless, the nearest creek to the Skerryvore Rock, and which, however exposed it may be, if compared with creeks elsewhere dignified with the name of Harbour, certainly affords as good prospect of shelter as any other part of the Island of Tyree, and is, in this respect, greatly to be preferred to any other place within sight of the Rock. A deputation of the Commissioners visited the Skerryvore in the month of July 1836, and concurred with the Engineer in regard to his choice of Hynish as a site for the Harbour and establishment.

Another most important point of inquiry was regarding the materials for building the Lighthouse; and on this subject the suggestions in a Report by the Engineer, of the 31st December 1835, were followed, which proposed the opening of quarries among the gneiss rocks around Quarries at Hynish. Hynish. Much facility was afforded by the liberality of the late Duke of Argyll, the proprietor of Tyree, who granted to the Commissioners free permission “to quarry materials for the purpose of the Lighthouse, on any part of the Argyll estates.” This freedom was generously continued by the present Duke, who has all along taken a lively interest in the success of the works. In terms, therefore, of the Engineer’s recommendations contained in the above noticed Report, Mr James Scott and fourteen quarriers were employed, during the summers of 1836 and 1837, in opening quarries, with very promising appearances of final success, among the gneiss rocks near Hynish Point. In the summer of 1837, Mr Scott and his party turned out about 3800 cubic feet of rock, capable of being applied to the purposes of squared masonry, and a very large quantity of stones fit for rubble work. This produce, although small, if contrasted with that of established quarries, is by no means despicable, when the force employed and all the disadvantages of the situation are considered; and if the nature of the material, which is full of rents and fissures (technically called dries and cutters), the frequent deceptions attending the opening of new quarries, the excessive hardness and unworkable nature of the rock, the quality and size of the blocks required to entitle them to claim a place in a marine tower, and the great loss of time, caused by the badness of the weather, be considered, it will not appear that Mr Scott and his party had been eating the bread of idleness.

In the mean time, measures had been taken for obtaining from his Grace the Duke of Argyll a feu of fifteen acres of ground at Hynish, for carrying on the works, with a view to its being finally occupied as an establishment for the crew of the vessel which was to attend the Lighthouse, and the families of the four lightkeepers, as well as for the site of the harbour. To this was added a lease of thirty acres, for the various purposes connected with a workyard, and such an establishment as seemed necessary for carrying on the work. A subject of anxious deliberation with the Board, was the construction of the harbour at Hynish for the vessels engaged in the service of the work; and the Commissioners, on the 24th May 1837, authorized the Engineer to make arrangements for commencing the formation of the Pier. The work was, accordingly, undertaken, in terms of his Reports of the 31st December 1835, and 27th February 1836; and the summer of 1837 was chiefly occupied in preparing a wharf, mostly composed of pierres-perdues,[6] and in the opening of the quarry already noticed. Such may serve as a brief and somewhat desultory notice of the work during the seasons of 1836 and 1837, after which it appeared to the Board that the operations must soon assume such an aspect as to require the superintendence of a committee of their number, as well as that of an Engineer specially entrusted with the management of the work.

[6] Blocks rough from the quarry, which are dropt or thrown promiscuously into the sea.

At the meeting of the Board, on the 8th December 1837, a Committee of their number was accordingly named, to superintend the erection of the Lighthouse. Skerryvore Committee appointed. This Committee consisted of—Robert Bruce, Esq., Sheriff of Argyllshire; Andrew Murray, Esq., Sheriff of Aberdeenshire; Robert Thomson, Esq., Sheriff of Caithness; and the late James Maconochie, Esq., Sheriff of Orkney and Zetland; and, shortly after its appointment, the Committee, on the motion of Mr Bruce, the Chairman, appointed me Engineer for the work.

Among the first matters which engaged the attention of this Committee, was a Report from the Engineer, dated the 30th January 1838, in which the necessity of erecting a wooden barrack, as a place of shelter for the workmen on the Rock, was pointed out; the general arrangements for carrying on the operations were described; and the building of a steam-tender, to act as a towing vessel for the stone lighters between the workyard in Tyree and the Rock, was also recommended. The Report was accompanied by a detailed requisition or estimate for the operations of the ensuing season, amounting to L.15,000 : 3 : 3; of which sum it was proposed to expend about one-third in building a steam-tender, and the rest in erecting the wooden barrack on the Rock, and in providing tools and materials for the work, as well as in the wages of men to be employed in preparing the foundation of the Lighthouse Tower, and in building the Pier, and dressing stones at Hynish.

The Committee, after considerable deliberation, sanctioned the various items of the estimate, but hesitated to embark in the expense of building a steamer, until a fruitless correspondence with various ports of the kingdom, with the view of purchasing an old vessel, satisfied them of the necessity of building a tender expressly for the purpose.

Offers were immediately received from various parties at Greenock for the preparation of the wooden barrack, which was soon afterwards commenced by the late Mr John Fleming, house-carpenter, who was the successful competitor.

CHAPTER III.
ON THE CONSTRUCTION OF LIGHTHOUSE TOWERS.

In this chapter I purpose, in the first place, to make a few observations regarding the construction of Lighthouse Towers in situations which are exposed to the assault of the waves, and afterwards to give a short notice of the design which I adopted for the Tower on the Skerryvore Rock. In making a design for a Lighthouse Tower in an exposed situation, numerous considerations at once present themselves to the Engineer; and it is difficult to assign to any one of them a priority in the train of thought which eventually conducts him to the formation of his plan. These considerations, however, may be conveniently divided into two classes:—1st, Those which refer to elements common to Lighthouses in all situations, and differ only in amount, such as the height of the Tower necessary for commanding a given visible horizon, and the accommodation required for the Lightkeepers and the Stores; and, 2d, Those which are peculiar to Towers in exposed situations, and which refer solely to their fitness to resist the force of the waves which tend to destroy them. The first class of considerations is so extremely simple, as to require few remarks in this place. The distance at which it is desirable that a light should be visible being ascertained, with reference to the nature of the surrounding seas and the extent to which any dangerous or foul ground lies seaward of the proposed Lighthouse, the height of the Tower is at once determined by means of the known relations which subsist between the spheroidicity of the earth, the effects of atmospheric refraction, and the height required for an object which is to be seen from a given distance. The question regarding the space to be provided in the interior of the Tower, can only be properly answered by a person who has a minute practical acquaintance with the peculiar wants and the internal economy of Lighthouses. The accommodation required for Lighthouses in exposed situations must, in a considerable degree, depend upon the greater or less facility of access to them, and the opportunities for replenishing the stores of all kinds which are in daily consumption. In such places, also, the risk of accidents naturally leads to the precaution of retaining additional Lightkeepers, and of having duplicates or even triplets of those parts of the apparatus that are liable to be injured. Of such circumstances, corresponding extension of the space devoted to the reception of Stores and the accommodation of the Lightkeepers, is the necessary consequence. In the long nights of a Scotch winter, when the lamps are kept burning for about seventeen hours, during which time they are never left for a moment without the superintendence of at least one Keeper, the care of the light, even in the most favourable situations, necessarily occupies at least two persons; but in places like the Eddystone, the Bell Rock, and the Skerryvore, where it sometimes happens that six or eight weeks elapse without its being possible to effect a landing, it has been thought necessary that there should never be fewer than three Keepers on duty. This addition to the ordinary establishment of a Lighthouse calls for a greater number of sleeping-cabins, and, at the same time, involves a corresponding increase in the supply of water, fuel and other provisions, requiring much additional stowage. So far, therefore, a Light Tower in an exposed situation, differs from one on shore only in the extent of its internal accommodation.

The second class of considerations, which must guide the Engineer in framing a design for a Light Tower which is exposed to the force of the waves, refers solely to the stability of the building.

The first observation which must occur to any one who considers the subject is, that we know little of the nature, amount and modifications of the forces, on the proper investigation of which the application of the principle which regulates the construction must be based. When it is recollected, that, so far from possessing any accurate information regarding the momentum of the waves, we have little more than conjecture to guide us, it will be obvious, that we are not in a situation to estimate the power or intensity of those shocks to which Sea Towers are subject; and much less can we pretend to deal with the variations of these forces which shoals and obstructing rocks produce, or to determine the power of the waves as destructive agents. No systematic or intelligible attempt has been made practically to measure the force of the waves, so as to furnish the Engineer with a constant to guide him in his attempts to oppose the inroads of the ocean. The only experiments, indeed, on the subject, with which I am acquainted, are those of Mr Thomas Stevenson, Civil-Engineer, who had long entertained the idea of registering the force of the impulse of the waves, and lately contrived an instrument for the purpose, which he has applied at various parts of the coast. I therefore gladly avail myself of the present opportunity, to give a brief statement of the results indicated by it, as contained in a paper by the inventor, which appeared in the Transactions of the Royal Society of Edinburgh of 20th January 1845, and of which a [digest] will be found in the Appendix, as any attempt to throw light upon this most obscure, but highly important subject, cannot fail to be interesting, not merely to the philosopher, but to the Marine Architect. It would naturally be expected, that the force of the waves should vary according to the season of the year, and the nature of the exposure, and this expectation is fully justified by the indications of the Marine Dynamometer. Thus it appears, that during five summer months of 1843 and 1844, the average indications registered at different places near Tyree and Skerryvore, gave 611 lb. of pressure per square foot of surface exposed to the waves; while the average for the winter months for the same places during those two years, gave 2086 lb. per square foot, or upwards of three times that of the summer months. It also appears, that the greatest result as yet obtained at Skerryvore Rock was 4335 lb. per square foot; while that observed on the Bell Rock was 3013 lb., or one-fourth part less than that of Skerryvore. But these experiments have not been continued long enough as yet to render them available for the Engineer. In the present state of our information, therefore, we cannot be said to possess the elements of exact investigation, and must consequently be guided chiefly by the results of those numerous cases which observation collects, and which reason arranges, in the form which constitutes what is called professional experience. This kind of experience can only be acquired by long habit in carefully observing the appearance and effects of waves in different situations, and under various circumstances. We must attend to their magnitude and velocity, their level in regard to the rocks on which they break, the height of the spray caused by their collision against the shore, the masses of rock which they have been able to move, and those which have successfully resisted their assault; as also, where such exist, the slopes of the shores produced by the waves, viewed in connection with the nature of the materials composing the beach, with many other transient features which an experienced eye seizes and fixes in the mind as elements of primary importance in determining the power of the sea to produce certain effects. Such phenomena, with all their features and circumstances, we may carry in our recollection; and by comparing them with what has been observed at places where we know that artificial works have resisted the shocks of the waves, we may in some cases successfully arrive at a conclusion as to what works will, at all events, be within the bounds of safety. We must not, however, in any case, venture to approach too near the limit of stability, so long as we continue to labour under our present disadvantages of defective information on some of the most important elements in the inquiry. If it be asked, therefore, how the size and form of buildings exposed to the shock of the waves are to be determined, the answer must be, that, in any given case, the problem is to be solved chiefly by the union of an extensive knowledge of what the sea has done against man, and how, and to what extent, man has succeeded in controlling the sea; together with a cautious comparison of the circumstances which modify and affect any given case which has not been the object of direct experience; nor does it seem possible as yet to found the art of Engineering, in so far as it refers to this class of works, upon any more exact basis. The uncertainty which must ever attend such reasoning can only, it is obvious, be dispelled by actual experience of the result; and time only can test the success of our schemes in cases of difficulty.

A primary inquiry, in regard to Towers in an exposed situation, is the question, whether their stability should depend upon their strength or their weight; or, in other words, on their cohesion, or their inertia? In preferring weight to strength, we more closely follow the course pointed out by the analogy of nature; and this must not be regarded as a mere notional advantage, for the more close the analogy between nature and our works, the less difficulty we shall experience in passing from nature to art, and the more directly will our observations on natural phenomena bear upon the artificial project. If, for example, we make a series of observations on the force of the sea, as exerted on masses of rock, and endeavour to draw from these observations some conclusions as to the amount and direction of that force, as exhibited by the masses of rock which resist it successfully and the forms which these masses assume, we shall pass naturally to the determination of the mass and form of a building which may be capable of opposing similar forces, as we conclude, with some reason, that the mass and form of the natural rock are exponents of the amount and direction of the forces they have so long continued to resist. It will readily be perceived, that we are in a very different and less advantageous position when we attempt, from such observations of natural phenomena, in which weight is solely concerned, to deduce the strength of an artificial fabric capable of resisting the same forces; for we must at once pass from one category to another, and endeavour to determine the strength of a comparatively light object which shall be able to sustain the same shock, which we know, by direct experience, may be resisted by a given weight. Another very obvious reason why we should prefer mass and weight to strength, as a source of stability, is, that the effect of mere inertia is constant and unchangeable in its nature; while the strength which results, even from the most judiciously disposed and well executed fixtures of a comparatively light fabric, is constantly subject to be impaired by the loosening of such fixtures, occasioned by the almost incessant tremor to which structures of this kind must be subject, from the beating of the waves.[7] Mass, therefore, seems to be a source of stability, the effect of which is at once apprehended by the mind, as more in harmony with the conservative principles of nature, and unquestionably less liable to be deteriorated than the strength, which depends upon the careful proportion and adjustment of parts.

[7] It was chiefly on these grounds that the Commissioners of Northern Lights, after consulting a Committee of the Royal Society of Edinburgh, and Messrs Cubitt and Rennie, Civil Engineers, rejected the design of Captain Sir Samuel Brown, R. N., who volunteered a proposal to build an Iron Pillar at the time that the erection of the Skerryvore Lighthouse was determined on in 1835.

Having satisfied himself that weight is the most eligible source of stability, the next step of the Engineer is to inquire what quantity of matter is necessary to produce stability, and what is the most advantageous form for its arrangement in a tower. The first question, which respects the mass to be employed, is, as already stated, one of the utmost difficulty, and can be solved by experience alone, directed by that natural sagacity which Smeaton, in his account of his own thoughts on the subject, with much naïveté, terms ‘feelings,’ in contradistinction to that more accurate process of deduction which he calls ‘calculation.’ It is very difficult, for example, to conceive that the waves could displace a cylindric block of granite, 25 feet in diameter and 10 feet high, which would contain about 380 tons, and we almost feel that they could not do so. If, in order to test the soundness of this expectation, we appeal to such experience as we possess, and apply to the largest vertical section of such a solid, the greatest force yet indicated by my brother’s Marine Dynamometer, which, as already stated, is 4335 lb. per square foot, we shall obtain a pressure of 484 tons, which, being reduced by one-half[8] for the loss of force occasioned by the convexity of the opposing cylindric surface, gives 242 tons, as the greatest force of the waves tending to displace the cylinder. But in the extreme case we have now supposed the solid will be entirely immersed in the water, and its efficient weight will thus be reduced by 140 tons, or the weight of an equal bulk of sea-water; and the remaining weight of 240 tons, by which it will resist the force of the waves, will be almost exactly equal to the pressure which they exert. This imaginary cylinder may, however, be regarded as still within the limits of safety, because the waves could not overturn it, unless their pressure exceeded the weight of the block in a ratio greater than that of its diameter to its height, which in this case is that of 25 to 10, or 2¹⁄₂ times. In order, therefore, to endanger the stability of the solid by overturning it, the pressure, instead of being 240 tons, must be 600 tons.[9] We have thus seen, that the cylinder is secure from the chance of being overturned; but we have yet to consider how far it is exempt from the risk of being displaced by the pressure of the waves, causing it to slide along the surface of the Rock, owing to deficiency of friction between the two surfaces in contact. The block, for our present purposes, may be regarded as monolithic, either being really so or as a mass composed of parts so united by joggles, treenails and mortar, as to be free from any tendency to disintegration by the force of the waves; and in this case the stability of the cylinder will depend upon the amount of friction opposing the pressure of the waves which tends to produce a sliding movement. It appears, by some experiments of M. Rondelet,[10] that the friction of a block of stone sliding on a chiselled floor of rock is equal to ⁷⁄₁₀ths of its own weight; and we should thus obtain in the present instance 168 tons, as the amount of friction tending to resist the pressure of the waves, which would therefore exert a power superior to that resistance by 74 tons.[11] But this excess of force would be easily neutralized by the adhesion of the mortar and the abutment of the block against the sides of the foundation pit into which Lighthouse Towers in such exposed places are generally sunk in the solid rock. When, in addition to these considerations, we learn that the solid frustum, or lower part of the Eddystone Tower, which has weathered so many storms for the last ninety years, does not greatly exceed in mass the imaginary cylindric block which I have spoken of, our confidence in the stability of the cylinder is greatly increased. Our belief receives a still farther confirmation from the fact, that the strongest instance recorded of the power of the waves, falls considerably short of the case which we have just imagined. The instance alluded to is given in Mr Lyell’s Geology, on the authority of the Reverend George Low, of Fetlar, in Zetland, who mentions, that a block, whose dimensions seem to give us reason to estimate its weight at nearly 300 tons (or about one-fifth less than that of the cylinder), was moved over a point, and thrown into the sea; and it must be remembered, that the form of this block, which was only 5 feet thick and about 40 feet long, rendered it very susceptible of a sliding motion, and must have greatly aided its transport. We may therefore not unreasonably conclude, that, in designing such a tower, it is safe to assume a mass which our own judgment and recorded facts seem to concur in pronouncing beyond the power of the greatest waves, as fixing the lowest limit to which the contents of the proposed edifice may be reduced.

[ [8] This reduction seems to be warranted by the results of some experiments of Bossut.

[ [9] This is the product of 240 tons, by the ratio of 2·5.

[10] L’art de bâtir.

[11] The number 168 is ⁷⁄₁₀ths of 240, which is the weight of the cylinder, reduced by the weight of an equal bulk of salt water; and 74 is the excess of 242 tons, the pressure of the waves, above 168, the amount of friction.

There are several circumstances, however, which tend to increase or diminish the stability of the same mass exposed to the same forces. Of these a very prominent one is the form of the mass, which may be so modified as to offer more or less resistance to the forces which assault the building. Thus a parallelopiped would be a much less suitable form for a sea tower than a cylinder, and so proportionally of all the polygonal prisms which may occur between these two extremes. I remember having heard it proposed, in the course of conversation, by a non-professional friend, that Lighthouse Towers might be formed in such a manner, that each horizontal section should be a wedge with its narrow end directed to the greatest assaulting force. This notion is in itself not destitute of ingenuity; for, if the circumstances to which it is to be adapted were constant, we should thereby present the form of least resistance, and, at the same time, the greatest depth and strength of the building to the line of greatest impulse. But the notion is wholly impracticable, because the direction of the winds and waves is so variable, as to render it almost certain that a Tower so constructed would, on some occasion, be assaulted in the line of its thinnest section; and thus, what might in one case be an advantage, would, in the event of such a change in the point of attack, become a great source of weakness, as the flat side of the wedge would then be opposed to the force, thereby presenting to the direct assault of the waves the largest surface, with, at the same time, the most disadvantageous disposition of the resisting matter. There seems little reason, therefore, for any doubt as to the circular section being practically the most suitable for a Tower exposed in every direction to the force of the waves.

Next to this, and hardly to be separated from it, inasmuch as it involves the question regarding the form of the Tower, is the position of the centre of gravity. The stability of any solid will, in general, greatly depend upon its centre of gravity being placed as low as possible; and the general sectional form which this notion of stability indicates is that of a triangle. This figure revolving on its vertical axis, must, of course, generate a cone as the solid, which has its centre of gravity most advantageously placed, while its rounded contour would oppose the least resistance which is attainable in every direction. Whether, therefore, we make strength or weight the source of stability, the conic frustum seems, abstractly speaking, the most advantageous form for a high Tower. But there are various considerations which concur to modify this general conclusion, and, in practice, to render the conical form less eligible than might at first be imagined. Of these considerations, the most prominent theoretically, although, I must confess, not the most influential in guiding our practice, is, that the base of the cone must in many cases meet the foundation on which the Tower is to stand, in such a manner, as to form an angular space in which the waves may break with violence. The second objection is more considerable in practice, and is founded on the disadvantageous arrangement of the materials, which would take place in a conic frustum carried to the great height which Lighthouse Towers must generally attain, in order to render them useful as sea-marks. Towards its top, the Tower cannot be assaulted with so great a force as at the base, or, rather, its top is entirely above the shock of heavy waves; and, as the conoidal solid should be prolate in proportion to the intensity of the shock which it must resist, it follows that, if the base be constructed as a frustum of a given cone, the top part ought to be formed of successive frusta of other cones, gradually less prolate than that of the base. But it is obvious, that the union of frusta of different cones, independently of the objection which might be urged against the sudden change of direction at their junction, as affording the waves a point for advantageous assault, would form a figure of inharmonious and unpleasing contour, circumstances which necessarily lead to the adoption of a curve osculating the outline of the successive frusta composing the Tower; and hence, we can hardly doubt, has really arisen in the mind of Smeaton the beautiful form which his genius invented for the Lighthouse Tower of the Eddystone, and which subsequent Engineers have contented themselves to copy, as the general outline which meets all the conditions of the problem which they have to solve. And here I cannot help observing, as an interesting, and by no means unusual, psychological fact, that men sometimes appear to be conducted to a right conclusion by an erroneous train of reasoning; and such, from his “Narrative,” we are led to believe, must have been the case with Smeaton in his own conception of the form most suitable for his great work. In that “Narrative” (§ 81), he seems to imply, that the trunk of an oak was the counterpart or antitype of that form which his (§ 246) “feelings, rather than calculations,” led him to prefer. Now, there is no analogy between the case of the tree and that of the Lighthouse, the tree being assaulted at the top, and the Lighthouse at the base; and although Smeaton goes on, in the course of the paragraph above alluded to, to suppose the branches to be cut off, and water to wash round the base of the oak, it is to be feared the analogy is not thereby strengthened; as the materials composing the tree and the tower are so different, that it is impossible to imagine that the same opposing forces can be resisted by similar properties in both. It is obvious, indeed, that Smeaton has unconsciously contrived to obscure his own clear conceptions in his attempt to connect them with a fancied natural analogy between a tree which is shaken by the wind acting on its bushy top, and which resists its enemy by the strength of its fibrous texture and wide-spreading ligamentous roots, and a tower of masonry, whose weight and friction alone enable it to meet the assault of the waves which wash round its base; and it is very singular, that, throughout his reasonings on this subject, he does not appear to have regarded those properties of the tree which he has most fitly characterized as “its elasticity,” and the “coherence of its parts.” One is tempted to conclude that Smeaton had, in the first place, reasoned quite soundly, and arrived by a perfectly legitimate process at his true conclusion; and that it was only in the vain attempt to justify these conclusions to others, and convey to them conceptions which a large class of minds can never receive, that he has misrepresented his own mode of reasoning. In the paragraph preceding that which refers to the tree (§ 80), he has, in point of fact, clearly developed the true views of the subject; and, with the single exception of the allusion to the oak, he has discussed the question throughout in a masterly style.

In a word, then, the sum of our knowledge appears to be contained in this proposition—That, as the stability of a sea-tower depends, cæteris paribus, on the lowness of its centre of gravity, the general notion of its form is that of a cone; but that, as the forces to which its several horizontal sections are opposed decrease towards its top in a rapid ratio, the solid should be generated by the revolution of some curve line convex to the axis of the tower, and gradually approaching to parallelism with it. And this is, in fact, a general description of the Eddystone Tower devised by Smeaton.

No. 1.

It is deserving of notice, as one of the many proofs which the records of antiquity afford of the similarity of the results of human thought in all ages, and of the truth of the Wise Man’s saying, that “there is nothing new under the sun,” that the ancient Egyptians appear to have had the same conceptions of the solid of stability that were present to the mind of the modern Engineer of the Eddystone Lighthouse. In the admirable work recently published by Sir J. Gardner Wilkinson on the Manners and Customs of the Ancient Egyptians, he gives, in the first volume of his second series, at page 253, a wood-cut, shewing the figure of the deity Pthah, under the symbol of stability, according to Egyptian conceptions. This symbol so closely and strikingly resembles the general appearance of the Eddystone, that I willingly give it a place in the text, ([No. 1]) denuded, however, of the arms and head-dress of the deity whom it shrouds.

In applying these general notions to the design of a Tower for the Skerryvore Rock, I was, of course, guided by numerous circumstances, which modified my views and produced the individual form of Tower which I have adopted. Since the days of Smeaton, when his magnificent Tower was lighted by common candles, the application of optical apparatus to Lighthouses has greatly altered the state of the case; and the improvement of the system in modern times has, in most instances, rendered a greater altitude of Tower desirable, in order to extend, as much as possible, the benefit of a system capable of illuminating the visible horizon of any Tower which human art can reasonably hope to construct. In the particular case of the Skerryvore, also, the great distance of the outlying rocks (some of which, as will be seen from the [chart], are 3 miles right seaward of the Lighthouse) concurs with the improvement of the Lights, in making it desirable that the Tower should be of considerable height, and that the light should command an extensive range. It was, therefore, from the first consideration of the subject, determined that the Light should be elevated about 150 feet above high water of spring tides, so as to illuminate a visible horizon of not less than 18 miles of radius; and, after much deliberation, and a full consideration of the infrequency of communication with the proposed Lighthouse from the great difficulty of landing on the Rock, and the consequent uncertainty of keeping up the supplies, I found that, for the convenient accommodation of the Lightkeepers and the suitable stowage of the stores, a void space of about 13,000 cubic feet would be required. These elements being fixed, the general proportions of the Tower came next to be considered.

In the Eddystone the radius of the base, at the level of high water of spring tides, is somewhat less than one-fifth of the height of the Tower above that level; while in the Bell Rock, at the same level, it is little more than one-seventh of the height. If, again, we suppose the curve of the Eddystone to be continued downwards to the level of low water, the radius (in so far as we may judge from sketching the continuation of a curve undefined by any geometrical property) would be rather more than one-fourth of the whole height above that level; while in the Bell Rock the proportion, in reference to the same level, is a little more than one-fifth. Viewing the whole height of the Skerryvore Tower above high water of spring tides as equal to 142 feet, and finding that, in the cases of the Eddystone and the Bell Rock, the radius of the horizontal section at that level is respectively one-fifth and one-seventh of the whole height; and again, viewing the extreme height of the Skerryvore Tower above low water of spring tides as equal to about 155 feet, and considering the proportionate radii of the Bell Rock and Eddystone (in so far as the latter is ascertainable) as respectively one-fifth and one-fourth of the heights of the top of the masonry above the level of low water, I finally decided upon giving the Tower at the Skerryvore such dimensions as would not be widely discordant with these general proportions. In this view, I determined that the radius of the base should not exceed 22 feet, on the level of about 4 feet above the high water mark, where I expected to obtain a solid foundation—a base which bears to the whole height of the Tower a proportion somewhat less than that of the Bell Rock, which is one-fifth. It so happens, that the diameter adopted is nearly the greatest which the Rock affords; for, although a glance at the accompanying plan of the Rock at high water ([Plate, No. III.]) would lead one to suppose that a more extended base might have been obtained, I found, after many careful examinations of the gullies and fissures which intersect it, that some of the concealed fissures run much farther into the Rock than might at first be imagined. The adoption of a much larger base, even had it been otherwise advisable, would therefore have involved some risk of the external ring of stones of the lowest course giving way by the yielding of an unsound part of the outer portion of the Rock to the pressure of the superincumbent mass, and might eventually have led to the destruction of the Tower.

No. 2.

The height of the Pillar having been finally fixed at 138·5 feet, and the radius of the base, at the level of about 4 feet above high water, at 21 feet, I next proceeded to consider the details of its proportions. Of the whole height of 138·5 feet, 18 were to be absorbed in a suitable capital for the Pillar, consisting of a parapet for the Lantern, an abacus, a cavetto, and a belt separating these from the shaft. The internal void I determined should be 12 feet in diameter, as the size most suitable for the reception of the lantern and apparatus; and this, combined with the choice of about 13,000 cubic feet of void already mentioned, fixed the height of the solid frustum at the base of the Tower at about 26 feet above the foundation. Having farther decided that the thinnest part of the walls, immediately under the belt-course which separates the capital from the shaft, should not be less than 2 feet thick, as necessary to give due solidity and strength to the walls, and prevent, by the breadth of the joints, the percolation through the walls of the water which might be furiously dashed against them in storms, I had nothing farther to do but to determine the nature of the line which should connect the extremities of the top and bottom radii of the Pillar. As I had already concluded that this line must, as in the Eddystone and Bell Rock, be a curve line, concave to the sea, I next proceeded to try the effects of various curves traced between these points, in giving a convenient and advantageous disposition of the materials, with regard to both the thickness of the walls and the mass of the solid frustum at the base of the Tower. These two points, as will be better understood by means of the accompanying diagram ([No. 2]), are separated from each other vertically 120·25 feet, and are horizontally distant from each other 13 feet, which is the excess of the bottom radius over that of the top of the shaft, or the consequent amount of what may be called the aggregate slope of the wall. The solid generated by the revolution of some curve line about the vertical axis of the building then becomes the shaft of the pillar. For this purpose I tried four different curves, the Parabola, Logarithmic, Hyperbola, and Conchoid, figures of which, upon the same scale, will be found in [Plate, No. IV.], with the position of the centre of gravity, which was carefully calculated, marked on each. The logarithmic curve I at once rejected, from its too near approach to a conic frustum, and the excessive thickness of the walls which such a figure would produce, where the hollow cylindric space for the internal accommodation commences at the level of 26 feet above the base. The parabolic form displeased my eye by the too rapid change of its slope near the base; and I had some difficulty in reconciling myself to the condition of the exterior ring of stones at the base, too much of the outer portion of each stone being left without the advantage of direct pressure from the superincumbent mass of the wall above. The two remaining pillars, derived from the hyperbolic and conchoidal[12] frusta, are nearly identical in form; and of these two curves I preferred the former, which gives the most advantageous arrangement of materials, in regard to stability, of all the four forms. This quality of advantageous proportion exists in these forms, in the ratio of the numbers in the last column of the following table:[13] which shews a slight superiority of the Hyperbolic over any of the other forms.

[12] The solid, in this case, would have been formed by the revolution of the interior conchoid of Nicomedes about its directrix; and its co-ordinates were kindly calculated for me by my late revered preceptor, Dr Wallace, Professor of Mathematics in the University of Edinburgh, who employed so many hours of his latter years in labours of kindness among his friends. This act of the Professor was the result of a conversation I had with him on the subject. Before I received his friendly communication, however, I had resolved to adopt the rectangular hyperbola, whose co-ordinates I had myself determined with this view some time before; and when I found that the conchoid and the hyperbola, traced between the two fixed points by means of the calculated co-ordinates, were so nearly coincident, that it was difficult to prevent their running into each other, even when drawn out on a large scale, I determined to adhere to my original purpose of adopting the latter curve as my guide.

[13] The last column of this table is derived as follows:—Assuming that the economic advantage of any proposed tower of given height and diameter at base and top, is inversely as the mass and the height of the centre of gravity above the base, and denoting these quantities by M and G respectively, the fraction 1G·M may be taken as an indication of the economic advantage of the proposed tower. Let 1G′·M′ express the economic advantage of another tower; then the advantage of the second tower, compared to that of the first, taken as unity, will be G·MG′·M′, by which expression, the last column in the table was calculated.

The shaft of the Skerryvore Pillar, accordingly, is a solid, generated by the revolution of a rectangular hyperbola about its asymptote as a vertical axis. Its exact height is 120·25 feet, and its diameter at the base 42 feet, and at the top 16 feet. The ordinates of the curve, at every foot of the height of the column, were carefully determined in feet to three places of decimals; and the Appendix contains a tabular view of the co-ordinates from which the working drawings were made at full size. The first 26 feet of height is a solid frustum, containing about 27,110 cubic feet, and weighing about 1990 tons.[14] Immediately above this level the walls are 9·58 feet thick, whence they gradually decrease throughout the whole height of the shaft, until at the belt they are reduced to 2 feet in thickness. Above the shaft rests a cylindric belt 18 inches deep; and this is surmounted by a cavetto 6 feet high, and having 3 feet of projection. The contour of this cavetto is that resulting from a quadrant of an ellipse revolving about the centre of the tower, with a radius of 8 feet on the level of its transverse axis; and the moulds for this curve were drawn at full size from co-ordinates calculated for the purpose. The cavetto supports an abacus 3 feet deep, the upper surface of which forms the balcony of the tower, and above it rest the parapet-wall and lantern.

[14] At the rate of 13·62 cubic feet of granite to a ton.

It may, perhaps, be not uninteresting to the reader to examine the woodcuts ([No. 3]), which shew, on one scale, the elevations of the Lighthouses of the Eddystone, the Bell Rock, and the Skerryvore, and exhibit the level of their foundations in relation to high water. They will also serve to give some idea of the proportionate masses of the three buildings. The position of the centre of gravity, as calculated from measurements of the solids, is also marked by a round black dot on each tower; and in the table following, I have given the cubic contents of each of these towers, the height of the centre of gravity above the base and the ratio of that quantity to the height of the tower.

No. 3.

EDDYSTONE.

SKERRYVORE.

BELL ROCK.

I come now to notice the few subordinate points in which the design of the Skerryvore Tower may be regarded as differing from those of the Eddystone and the Bell Rock. In glancing at the contrasted figures of the three buildings, it will be at once observed that the outline of the Skerryvore approaches more nearly to that of a conic frustum than the other two. To the adoption of this form, various considerations induced me; and these I shall very briefly detail. In the first place, it seemed to me that, in both the Bell Rock and the Eddystone, the thickness of the walls had been reduced to the lowest limits of safety towards the top; and the effects of the sea and wind acting upon a heavy cornice, cause a degree of tremor which I felt satisfied would not occur in a building with thicker walls. The effect of thickening the walls at the top, is, of course, cæteris paribus, to diminish the projection of the base, and thus to produce less concavity of figure, and consequently a nearer approximation to the contour of a conic frustum. I have already stated, that this excess of the bottom radius over that of the top, is in the Skerryvore Tower 13 feet, and that the height of the shaft is 120·25 feet. The quotient resulting from the division of the height by the excess of bottom radius over that at the top is 9·27; and, if the figure had been conical, this number would have given a measure of the slope of the walls throughout. There can be little doubt that the more nearly we approach to the perpendicular, the more fully do the stones at the base receive the effect of the pressure of the superincumbent mass as a means of retaining them in their places, and the more perfectly does this pressure act as a bond of union among the parts of the Tower. This consideration materially weighed with me in making a more near approach to the conic frustum, which, next to the perpendicular wall, must, other circumstances being equal, possess the property of pressing the mass below with a greater weight, and in a more advantageous manner, than a curved outline in which the stones at the base are necessarily farther removed from the line of the vertical pressure of the mass at the top.[15] This vertical pressure operates in preventing any stone being withdrawn from the wall in a manner which, to my mind, is much more satisfactory than an excessive refinement in dovetailing and joggling, which I consider as chiefly useful in the early stages of the progress of a work, when it is exposed to storms, and before the superstructure is raised to such a height as to prevent seas from breaking right over it.

[15] It is most satisfactory to find that the views expressed above, regarding the eligibility of the conical form, seem to have the sanction of the late Dr Thomas Young, who appears to have connected his preference of this form with its greater efficiency as a source of friction among the parts of a building. In his syllabus of Lectures, under the section “Architecture,” he thus speaks: “For a Lighthouse where a great force of wind and water was to be resisted, Mr Smeaton chose a curve convex to the axis. In such a case, the strength depends more on weight than on cohesion, and also in a considerable degree on the friction which is the effect of that weight. Perhaps a cone would be an eligible form.”

If these views be substantially correct, it may not, perhaps, be altogether inadmissible (without, however, venturing to enunciate any general law) to conclude, that, in the three Lighthouses of the Eddystone, the Bell Rock, and the Skerryvore, this source of union among the outer stones of the lower courses must bear some proportion to the numbers 753, 659, and 927, which are the quotients of the height of the column, divided by the difference of the top and bottom radii of the shaft in each case respectively. This consideration seems too important to be entirely overlooked; and I conceive that, by following out this view, I have been enabled to depart with perfect safety from the intricate and elaborate work required for the connection of the materials by means of dovetailing and joggling, which the adoption of a more concave outline (in which the vertical pressure could not have been so advantageously transmitted to the outer stones of the base), would perhaps have rendered advisable. In the case of the Bell Rock, however, whose construction, in regard to this property, is the least advantageous of the three buildings, it must be borne in mind that the Tower is covered to the depth of 15 feet at spring tides, and that this principle of vertical pressure could not have been safely appealed to during the whole time which intervened between the commencement of the building and the attainment of a height sufficient to render it available, which, in a Tower having so great a part submerged, was of necessity much prolonged. The stones were thus exposed to the full effect of heavy seas, at all levels, during two entire winters, and could not therefore have been safely left, without being kept together by numerous ties and dovetails. It also seemed important, in designing that Tower, with reference to the rise of tide, to give its lower part a sloping form, as the least likely to obstruct the free passage of the waves. The outer stones of the lower courses were also selected of unusual length inwards, so as to bring them more under the influence of the vertical pressure of the upper wall.

Before leaving this subject, I may remark, that it is quite possible to construct a Tower of a curved form, in such a manner, that the pressure of the upper part of the pillar shall be distributed to the greatest advantage on every stone, by building the outer walls as inverted arches, so that the section of each stone shall be that of a voussoir, with joints perpendicular to the successive tangents of the curve. This arrangement of the stones is, in fact, practised in sea walls of various kinds, and has even been recommended for circular Towers in an ingenious paper in the Transactions of the Royal Scottish Society of Arts. But in many situations, and at Skerryvore in particular, this mode of transmitting the pressure, so as to throw it perpendicular to the beds of the stones, is inadmissible, as conducing to or involving a greater evil. The evil has already been noticed, and consists in the thrust of the lowest stone (which is of course inclined to the horizon) having a tendency to push out the sides of the Rock on which the Tower is built. This fear, where the Towers are to be placed on small steep rocks or pinnacles, and more especially when these Rocks are traversed by veins nearly vertical, is by no means visionary; and there is good reason to apprehend, that the pressure thus resulting in a line considerably inclined to the plane of cleavage, might throw outwards a thin portion of rock, which, under the more conservative influence of a vertical pressure, might continue to retain its connection with the rest of the Rock unimpaired for ages.

Another method of, in some degree, increasing the resistance of a Sea Tower to a horizontal thrust, if such aid be required, is to give the line of courses a continuous spiral form, instead of building them in successive horizontal layers. Were there reason to fear that the entire dislocation of the building might take place in a plane nearly horizontal, this method seems more calculated to counteract the danger than the use of dowels or joggles passing from the course below to the course above; but, as this is one of the accidents least to be apprehended, there does not seem any good ground for resorting to a mode of structure which would lead to considerable intricacy of workmanship, and would, in practice, be attended with difficulty in obtaining a proper vertical bond or union among the several stones.

The only remaining point, in which the example furnished by the Eddystone and Bell Rock Lighthouses has been at all materially departed from, is (as has already been hinted at by an unavoidable anticipation) the mode of uniting the different parts of the masonry together. In both these Towers the stones were dovetailed throughout the buildings, chiefly (at least in the case of the Bell Rock where the foundation was so much below the tide) with the view of preventing the sea from washing away the courses which might be left exposed to the winter storms before the weight of the superstructure had been brought to bear upon them. In the upper part of the Bell Rock my father also introduced a kind of band joggle, which consists of a flat ribband of stone raised upon the upper bed of one course, and fitting into a corresponding groove cut in the under bed of the course above; and this system of tying the adjoining courses together also forms a chief feature in his design for a Lighthouse on the Wolf Rock.[16] When the great pressure of the superstructure of these Towers, however, and the effect of the mortar are considered, there seems little probability of one course being dislocated, in defiance of the friction resulting from the weight of the column. An impulse sufficient to produce such an effect would tend to overset the whole superstructure from mere deficiency in weight, and in this case the joggle would have little effect. But if joggles be thought necessary for this purpose, the ribband form certainly produces a better arrangement than that of the cubic joggles employed by Smeaton for connecting the adjoining courses of his building together, as the sectional strength of these scattered square joggles is very small compared to the effect of a shock which could be supposed capable of moving the whole mass of a Tower. In the lower parts of the Skerryvore Tower, I entirely dispensed with dovetailing and joggles between the courses, and thus avoided much expensive dressing of materials. The stones were retained in their places during the early progress of the work, chiefly by common diamond joggles, and the courses were temporarily united to each other by wooden treenails, like those used in the Eddystone and Bell Rock. These treenails had split ends, with small wedges of hardwood loosely inserted, which being forced against the bottom of the holes in the course below, into which the treenails were driven, expanded their lower ends until they pressed against the sides of the holes; while their tops were made tight by similar wedges driven into them with a mallet. I have, however, adopted the ribband-joggle in the higher part of the Tower, where the walls begin to get thin in the very same manner as at the Bell Rock, where it was used, partly that it might counteract any tendency to a spreading outwards of the stones, and partly that it might operate as a kind of false joint to exclude the water which, when pressed with great violence against the Tower, is apt to be forced through a straight or plain joint. The stones in the higher courses throughout each ring are also connected at the ends by double dovetailed joggles, which unite the two adjoining stones; and the walls are, besides, tied together at various points by means of the floor stones, which are all connected by dovetails let into large circular stones which form the centres of the floors. I also ventured to leave out the metallic ties at the cornice, which consisted, at the Eddystone, of chains, and, at the Bell Rock, of copper rings. The reasons which induced me to adopt this change I need not here enlarge upon. It is sufficient to state, that I believe I have nearly balanced the forces which would have tended to throw the cornice outwards, had a greater disproportion existed in the weight of the outer and inner parts of the cavetto, and to point out ([Plate VII.]) that the Lightroom or highest floor occurs, at such a level, as of itself to answer all the ends which metallic ties could have served.

[16] Account of the Bell Rock Lighthouse, Plate XXI.

CHAPTER IV.
OPERATIONS OF 1838.

The hazardous nature of the anchorage, and the consequent difficulty of mooring a vessel in the neighbourhood of the Skerryvore Rock, induced me, from the first, to consider it as a matter of great importance, even at a large expenditure of time and money, to erect Temporary Barrack on Rock. some temporary dwelling on the Rock for the accommodation of the people engaged in the work, with the view of rendering the operations less dependent on the state of the sea, which varied with every wind. So important, indeed, did this object appear to me, that I was at times apt to look upon it as an indispensable step towards ultimate success. That opinion was amply confirmed during our first season’s operations, by the experience of the oft-recurring difficulty of returning to the moorings when driven away by stress of weather, together with the daily risk and loss of time in landing the workmen in small boats, even in weather when they could be profitably occupied if once placed on this small terra firma. With this view, I naturally turned to the same plan which had been adopted at the Bell Rock, where the temporary barrack stood the test of five winters. That structure, which is represented in [Plate No. V.], and is particularly described in the Appendix to my father’s Account of the Bell Rock Lighthouse, consisted of an open framework of six logs, about 47 feet long and 13 inches square, assembled in such a manner as to form by their union a hexagonal pyramid, on the top of which rested a wooden turret; the whole erection rising to the height of about 60 feet above the rock. This pyramidal framework was strongly trussed and tied; and, being open at the lower part, offered little resistance to the waves. The upper part contained a gallery for keeping various stores and such materials as could not be safely left on the Rock, even in the finest weather; but it was framed of lighter materials, so as to admit of its yielding easily to any extraordinary waves, without involving injury to the principal part of the structure, by offering great resistance to the sea. The turret on the top was in the form of a twelve-sided prism, 12 feet in diameter, and 30 feet high, and was securely attached, by means of the ties and braces shewn in the [drawing], to the apex of the pyramid, which entered into the lower part of it. The small space which the turret afforded was, with the utmost economy of room, divided into three storeys, of which the lower was entirely taken up by the kitchen and the bread-store, a great deal of room being occupied by the main beams of the pyramid which passed through its centre. The next storey was subdivided into two chambers, of which one was appropriated to the foreman of the works and the landing-master, while the other was set apart for myself; and the top storey, which was surmounted by a small lantern and ventilator, formed a barrack room, capable of containing 30 people. Of the comforts and discomforts of this habitation I shall at some future time have occasion to speak. I merely draw attention to its erection at present, as an operation, which it was most desirable should precede every other work on the Rock. One of the first proceedings, therefore, was to obtain estimates for the preparation of this log-house, which, in order to avoid loss of time in making adjustments on the Rock, was to be carefully fitted up in the workyard of the contractor before being shipped. Drawings and a specification were accordingly prepared, and submitted to several carpenters in Greenock, who gave in offers for the work; and it was finally commenced in the month of March, by the late Mr John Fleming, who was the successful offerer.

Tools and Machinery. It was also necessary to provide a large assortment of quarriers’ and masons’ tools of every kind; and many cranes, crabs, anchors, mooring buoys and other implements were ordered, according to detailed specifications and drawings. These preparations necessarily occupied the early part of the year 1838.

From the extent of the foul ground round the Skerryvore, and the absence of good harbours in the neighbourhood, it was foreseen at the outset that the operation of landing about 6000 tons of materials on the Rock could not be accomplished by means of sailing vessels with that degree of certainty or regularity which was desirable, in order to obtain the full benefit of the short working season which the climate of the Western Hebrides affords; and the necessity for providing a Steam Tender for the Works. steam tender was, therefore, generally admitted. It has already been stated, that, in order to avoid the expense attending the building of a vessel for this purpose, application was made at the principal ports of the kingdom, with the view of purchasing a suitable vessel; but, although twenty-four vessels of nearly the required dimensions were offered for sale, not one of them was considered fit for such a service, the great majority being light craft, such as are generally used in river and port navigation. It was therefore found necessary to build a steamer; for which purpose, specifications and drawings were prepared, and after receiving various tenders from respectable parties, a contract was entered into with Messrs Menzies and Sons, shipbuilders, and Messrs J. B. Maxton and Co., engineers, both of Leith, for building a steamer of 150 tons, with two engines of 30 horse power each.

The use of a steamer, at the very outset of the works, would doubtless have proved of the greatest service in the erection of the barrack on the Rock, and would have materially lightened our cares and toils; but I am not sure that I should have acquired so thorough an acquaintance with the difficulties and dangers of the Skerryvore, or that I should have been so well prepared for all the obstacles that presented themselves in the after parts of the work, had the first season’s operations been conducted under those advantages which are always derived from the use of steam-power. As it was, we had much to bear from the smallness of the Lighthouse Tender, named the Pharos, a vessel of 36 tons, new register, which was all the regular shipping attendance we possessed during this first season; and the inconvenience arising from her heavy pitching, was, to landsmen, by no means the least evil to be endured. But the frequent loss of opportunities, of which we might easily have availed ourselves, if we had possessed the command of steam-power, and the danger and difficulty of managing a sailing vessel in the foul ground near the Rock, and between it and Tyree, were, perhaps, even more felt by the seamen than by the landsmen; and if the experience of a single year’s work can form any ground for an estimate of the length of time required for building the Skerryvore Lighthouse, with a sailing vessel, I should say, we must still (even in 1845) have been engaged in the masonry part of the work, which was finished on the 25th July 1842.

About the middle of April, arrangements were made with Mr Charles Neilson, a builder in Aberdeen, to select granite masons for the works at the Skerryvore, as it was expected that the operation of dressing stones for the Tower would be begun in the ensuing summer; and it was also obvious, that their services would be required in excavating seats for the supports of the Barrack-house on the Rock. Employment and Wages of Workmen. Masons were accordingly selected, and engaged on the terms stated in the following letter to Mr James Scott, the Foreman, who was sent to Aberdeen to assist in choosing the men:—“Although it is difficult to fix the precise number of men who may be required, during the progress of the works, as this must, in some measure, depend upon the produce of the quarries at Hynish, and of those to be opened in Mull, you may, in the mean time, engage thirty masons or stone-cutters, twelve quarriers, and three or four smiths, for two years of certain employment. With regard to the rate of wages to be paid to the men, this will, in some measure, depend upon the demand for the season at Aberdeen; it is, at all events, expected, that they will on no account exceed the rate of 3s. 10d. per day for masons, and 2s. 6d. per day for quarriers, as paid last season during the long day, or from the 1st of February till 31st of October; and for the short day during the remaining three months, 3s. for the masons, and 2s. for the quarriers, from 1st November till 31st January.

“It is intended that subsistence money shall be paid to such of the families or relatives of the workmen as may require it; and that their wages shall be fully settled monthly, deducting the subsistence money advanced to their relatives. A Store will be kept at the works by the Lighthouse Board, from which provisions will be served out at stated periods, to be fixed by the storekeeper; and these provisions shall be sold to the workmen at the cost prices at which such stores are laid in. Barrack accommodation or lodgings, with cooking, will also, as formerly, be allowed to the men free of expense.”

Progress of the outfit for the season’s operations. Early in the month of May the preparation of the wooden barrack for the Rock had been completed, and the whole had been set up in the workyard at Greenock; and when I visited it for the last time about the 5th of that month, I found it all ready for shipment, excepting some additional iron ties, which I ordered for securing the turret to the top of the pyramid, which were to be applied at the level of the floor of the upper or barrack-room storey. I also found that the moorings, including the mushroom anchors and chains, and the workyard materials, consisting of several cranes, trucks, a janker for the transport of timber, and a Woolwich sling-cart for carrying stones to the various sheds, were in the course of preparation. A large assortment of masons’ and quarriers’ tools was at the same time ready for shipment at Aberdeen. Early in June, a vessel called the Duke of Montrose was chartered to carry coals to Tyree, both for household purposes and for the work; and two small portable smiths’ forges were prepared for use on the Rock.

In providing the means of efficiently carrying on so many complicated operations in a situation so difficult and remote, it is impossible, even with the greatest foresight, to avoid omissions; while delay of a most injurious kind may result from very trivial wants. Even the omission of a handful of sand, or a piece of clay, might effectually stop for a season the progress of plans, in the maturing of which hundreds of pounds had been expended. Accordingly, although I had bestowed all the forethought which I could give to the various details of the preparation for the season (of which I found it absolutely indispensable to be personally aware, even to the extent of the cooking dishes), new wants were continually springing up, and new delays occasioned, so that it was not until the evening of the 23d of June that I could Embark for Skerryvore. embark at Tobermory in the Pharos Lighthouse Tender, commanded by Mr Thomas Macurich, with all the requisites on board for commencing the season’s operations. Next morning we moored off Hynish Point about three o’clock, and, from the roughness of the passage, were not unwilling to land at that early hour. Here I found that Mr Scott, the foreman of the workyard, had, notwithstanding the unworkable nature of the Rock, more particularly afterwards noticed, procured about sixty fine blocks of gneiss, as the produce of the Tyree quarries, which had been wrought for upwards of 15 months; and had at the same time completed the masonry of a range of buildings for stores and barracks, capable of containing upwards of 100 men, and had built about 100 feet in length of a landing-pier, reaching nearly to low-water mark. A magazine for gunpowder, of which a considerable stock was required for quarrying purposes, had also been built; and a piece of garden ground had been inclosed and stocked for the use of the people to be employed at the works. Measures had also been taken for inclosing the ground, which had been feued by the Board from the Duke of Argyll. This day being Sunday, nothing was done at Hynish, and we waited until next morning before sailing for the Rock.

25th June.—Sailed in the Pharos from Hynish Bay this morning about six, with Mr Scott, the foreman of the workyard, and one or two masons on board; but, having a foul wind during the early part of the day, and the weather falling afterwards calm, it was not until three in the morning of the 26th that we reached the Rock.

26th June.—Our first step was to Lay down Moorings, and try to land on the Rock.lay down moorings for the tender as near the Rock as seemed to be consistent with safety. The position chosen by Mr Macurich, who commanded the vessel, was to the S.S.E. of the Rock, about a quarter of a mile off, and in 13 fathoms water, on an irregular rocky bottom. About half-past five I attempted a landing on the Rock, but there was a great deal too much sea. The vessel was pitching the bowsprit under at her moorings, and the surf broke into the creek where landings are generally made, in such a manner as to render it quite impossible to get near the Rock. After hanging on our oars in the boat for nearly an hour, in the hope of a smooth lull between the heavy seas, we returned to the vessel, and, as the wind still freshened from the S.E., we reefed the mainsail and set the first jib, and steered for the Mull shores, where, about ten at night, we came to an anchor in Loch Loich, not far from the Island of Iona.

27th June.—Next day also being unsuitable for attempting to reach the Skerryvore, the vessel lay in North Bay, and the early part of the day was spent in a careful examination of the granite Rocks of the district called Driven to Mull. Ross of Mull, with the view of establishing quarries there; as our experience of the unsatisfactoriness of working the Tyree quarries during fifteen months had frequently led me to anticipate the necessity of soon seeking a supply of materials in some other quarter. In this district an almost inexhaustible supply of flesh-coloured granite was found, not certainly of the hardest description, but singularly equal and homogeneous in its texture. I therefore made a general survey of the neighbouring localities, with a view to select the best position for opening quarries and establishing a landing place or wharf for shipping the materials, as well as for erecting barracks for the workmen. In the afternoon, I embarked at the call of Mr Macurich, to attempt another landing on the Skerryvore; but as the wind soon fell calm, we did very little good until evening, when some progress was made in stretching across towards the Rock.

28th June.—At nine this morning, we reached our moorings at the Rock, but there was still so much surf that a landing could not be attempted till mid-day, when I went with Mr Macurich in the boat, and with some difficulty contrived to spring on the Rock, after which the boat returned to the vessel for the rest of the party. While left alone on this sea-beaten Rock, on which I had landed with so much difficulty, and as I watched the waves, of which every succeeding one seemed to rise higher than the last, the idea was for a few minutes forcibly impressed on my mind, that it might, probably, be found impracticable to remove me from the Rock, and I could not avoid indulging in those unaccountable fancies which lead men to speculate with something like pleasure upon the horrors of their seemingly impending fate. These reflections were rendered more impressive by the thought that many human beings must have perished amongst those rocks. A consideration, however, of the rarity of an opportunity of landing on the Rock, and the necessary shortness of our stay, soon recalled me to my duty, and before the boat returned with a few of the workmen, I had projected some arrangements as to the first step to be taken in erecting the framework of the barrack-house. The second landing was more easily effected, as the tide had fallen, and the landing-place was more sheltered, First day’s work on the Rock. so that we were the more emboldened to make a fair commencement of operations. It was a day of great bustle and interest, the work consisting in chalking out and marking on the Rock with paint, the sites of the Lighthouse-Tower, and the wooden barrack, and the positions for cranes, crabs, and ring-bolts for guys and other tackling, as well as ascertaining such dimensions as would enable me at once to proceed to fit up the log-house, or barrack, at our next landing. In that way, we spent four hours on the Rock, much to the annoyance of the seals and the innumerable sea-fowl, which we drove from their favourite haunts. During the whole day, the sun had great power; and the smell from the cast-away feathers and the soil of the sea-fowl was extremely disagreeable. I was amazed to find that those animals should select, as their place of repose, a rock in the Atlantic, intersected by deep gullies which are never dry, with only one pinnacle, about 5 feet in diameter, raised about 16 feet above the sea. while the greater part is only 5 feet above high water. Yet, in a crevice of this Rock, I found an egg resting on a few downy feathers, which the first wave must have infallibly washed away! After the day’s work on the Rock, we sailed for Tyree, but did not reach the workyard till next morning at nine; and a long day of bustle and hurry was spent there in preparing provisions, timber, ring-bolts, chains and all sorts of tackling for the operations connected with the erection of the barrack on the Rock. On the evening of the 30th June, I sailed for Greenock, whence I trusted soon to return to the Skerryvore with the whole of the materials, to commence operations.

It seldom happens that human expectations are fully realised, especially in matters which excite a strong interest in the mind, and thus lead one to desire a more rapid progress than usual. But this is peculiarly true in all arrangements which depend on the co-operation of many persons; and so I experienced on my visit to Greenock and Glasgow, where I had given orders for Shipment of all the materials at Glasgow and Greenock. shipping all the machinery and apparatus required for carrying on the works, such as cranes, trucks, boats, blocks and tackle, anchors, coals, grindstones, stucco, pavement, mats and fascines for blasting, clay for puddling, shear-poles, and innumerable small utensils, some of no great value, but all necessary to the success of the work. The great bulk of those materials were despatched by a vessel called the New Leven, and part by the Mary Clark, on the 24th July; but it was not until the 30th that the Pharos Lighthouse tender was fully loaded, on the morning of which day I again embarked at Greenock for the Skerryvore Rock. The weather proving somewhat unfavourable, we were forced (being very heavily laden) to pass through the Crinan Canal, instead of going round the Mull of Kintyre, so that it was not till the morning of the 4th August that we landed at Reach Tyree. Hynish, in Tyree. Here I found some farther progress had been made in building the barracks for the men, some of the houses being already roofed and slated. The quarries, too, had turned out stones sufficient for about four of the lowest courses of the Tower, a quantity which might be estimated at about 7920 cubic feet. Next day (August 5th), the wind blowing strong from the S.S.W., we were forced to leave Hynish Bay, Driven to Mull. and retreat before a very heavy sea to Tobermory. We immediately sailed again, and made for Loch Erin, a small creek in the Island of Coll, as being nearer to Hynish and better adapted for enabling us to take advantage of any sudden improvement in the weather. On our arrival at this singular natural haven, at nine in the evening, I was glad to find the New Leven, before mentioned as having loaded materials at Greenock lying already there, waiting a favourable change of wind. Next morning we weighed anchor, Return to Tyree. and sailed along with that vessel for Hynish, where she was immediately discharged of her cargo, which was chiefly intended for the workyard there, and took in materials for the erection of the barrack on the Skerryvore Rock.

7th August.—We this morning took on board various tools and implements for the Rock, together with workmen to the number of four carpenters, sixteen masons and quarriers, and a smith, along with Mr George Middlemiss, as foreman. Having sailed with a northerly wind, we made a landing about noon, First good day’s work on the Rock. and had what may be called our first entire day of work on the Rock. Our work was by no means easy, as we had to erect shear-poles and fix crabs for landing the materials, and to lash every article that was landed, with great care down to ring-bolts on the Rock, which a few of the masons were fixing, while the rest of the people were discharging the vessel. All this was attended with a good deal of trouble, and it required my constant attention to keep everything going on in a fair train, so as to prevent one party of workmen requiring to wait for another; but, after eight hours of very hard work, I had the satisfaction of seeing all the materials which had been landed left in a secure state. The extreme smoothness of the surface of the Rock greatly impeded the landing of materials; for as yet we had no tramways on which wheeled trucks could be moved, and the transport by hand of heavy materials over so irregular and slippery a surface was attended with considerable danger. A short trial was this day made of boring one of the holes for the stancheons or bats, by which the timbers of the Barrack were to be secured to the Rock; and I found, that with a jumper of 3¹⁄₂ inches diameter, a depth of about 3 inches was bored in one hour. The commencement of the operations involved much labour and considerable discomfort; but it invariably happened throughout the work, that in spite of all the fatigue and privation attending a day’s work on this unsheltered Rock, the landsmen were for the most part sorry to exchange it for the ship, which rolled so heavily as to leave few free from sea-sickness, and to deprive most of the workmen of sleep at night, even after their unusually great exertions during the day.

On leaving the Rock at night we had the greatest difficulty in boarding the Pharos with two boats containing upwards of thirty-two persons, as the vessel rolled so heavily, that there was great danger of the boats being thrown right upon her deck. Next morning (8th August) we landed, with some sea running, about nine o’clock, before which hour it was impracticable, owing to the surf in the landing creek. Our first work was to prepare the tackling for landing the heavy materials from the New Leven, which came up about eleven o’clock, and was made fast by a warp to the Pharos. We next took means for fixing the smith’s forge on the Rock and preparing the fixtures for the crab, which stood on the point of rock to the westward (see [Plate III.]), and served chiefly for raising the beams of the log-house into their places. The greater part of the day, till half-past eight in the evening (when it became dark), was spent in lining off with accuracy the site of the supports of the wooden barrack, and in landing and fixing by strong lashings to the Rock, all the principal timbers and iron fixtures. The spot in which the framework of the first barrack was placed, will be seen by reference to [Plate III.] The Rock was at this place a good deal lower than the site afterwards adopted for the barrack. The high water of spring-tides rose 2¹⁄₂ feet upon the legs or main beams; but this site had many advantages, as it left more room for operations at or near the Tower itself than could have been obtained in any other position.

We also made some progress in erecting a wooden shed round the smith’s forge, to protect him and his fire from the wind and the spray of the sea. As we left the Rock in the boats, speculating on the prospect of getting the whole of the materials discharged in the course of next day, it was remarked that the northern sky was very clear, and that the wind had entirely fallen. The great and sudden stillness of the air, which permitted every ripple on the ocean to be heard, was regarded by Mr Macurich and the seamen generally, as the forerunner of a change; and the moon, which rose red and fiery, confirmed their fears of a gale. Nor were they wrong in their forebodings. Sudden gale, and great peril to the vessels.About midnight there was a stiff breeze from the S.E., which induced the master of the New Leven to hoist sail, cast loose from us, and run; and had not the seaman on watch on the deck of the Pharos fallen asleep in consequence of excessive fatigue, there can be little doubt we should have been at once called to follow her example, if, indeed, we had not led the way. No sooner, however, did Mr Macurich become aware of the state of the wind, which was blowing very strong at S.S.E. right into the landing place, than he roused me about two o’clock. At this time there was a very heavy sea; the little vessel was pitching her forecastle under, and we had to contend with a strong tide combined with the wind against us in working clear of the Rock, from which our moorings were not more than a quarter of a mile to windward; while from the place where we lay, half of the horizon was foul ground, all lying to our leeward. We soon set sail, but in vain tried to weather the sunk rock Bo-Rhua, whose large black mass (after having imagined ourselves past it) we discovered encircled by a wreath of white foam within less than a cable’s length of us. The heavy seas we encountered had greatly deceived us as to our progress, and thick blinding showers of rain made it difficult to see far beyond the vessel’s head. Such was the precarious and dangerous position of the vessel, that had an attempt been made to tack her amidst the surf which came rolling off the Rock, she would most probably have missed stays, the consequence of which would have been the inevitable loss of the vessel and of every soul on board. In this dilemma we were obliged to resort to a less dangerous expedient, by wearing the ship and running her through the narrow passage between Bo-Rhua and the sunk rocks, about 300 yards to the W.N.W. of it, although this was a most hazardous attempt, as we had then little or no knowledge of that dangerous and intricate passage. A more anxious night I never spent; there being upwards of thirty people on board, with the prospect, during several hours, of the vessel striking every minute. And here I must award due praise to Mr Macurich for the coolness and intrepidity which he on this occasion displayed, and the calmness with which he gave his orders to the crew; and as I stood in the companion, telling him the time at intervals of five minutes, so as to enable him the better to judge of the vessel’s way through the water, I could not but remark the necessity for silence on the part of the master of a vessel in cases of difficulty. The workmen were told to be getting ready for landing, but we did not make them aware of the full extent of the danger; and to avoid confusion, they were not permitted to come on deck. We had no sooner cleared the sunk rocks already alluded to, than we were in fear of the great reef of Boinshly, and the heavy seas which were breaking over the foul ground all round it. In this way we spent a night of almost uninterrupted anxiety until daylight, and at eight in the morning Reach Hynish in safety. we came to the moorings in Hynish Bay, after a hard struggle against wind and tide and a very heavy sea, which made us hang dead a long time off Hynish Point. At one time I feared we should have been forced, as I had been, when returning from my first unsuccessful and discouraging attempt to land on the Skerryvore in 1836, to go round the west side of Tyree and Coll, which is a very foul coast; and when we did round Hynish Point, it was almost at the expense of our boat, which the heavy sea had nearly swept away from us. After all this anxiety about our safety and discomfort from rain, wind, and spray, during five or six hours, we were not sorry to set foot even on the wild shores of Tyree; and I trust there were none who did not gratefully acknowledge the protecting care of Almighty God, in preserving us through such peril.

Detained by bad weather four days at Hynish. It was not until Monday the 13th that a landing was again effected on the rock, as the wind continued to blow strongly from the south; and the intervening four days were spent in Hynish Bay, landing in the morning, and again returning to the vessel in the evening. During this time I was engaged in making drawings of some of the lower courses of the Lighthouse Tower, with a view to fix finally upon dimensions, from which working drawings and wooden moulds for cutting the stones could be made. The only alleviation of my impatience at being detained at Hynish was the satisfaction of seeing some 20 feet of the pier founded at low water. Late in the evening of the 13th August we again landed on the Rock, when we found time, before dark, to complete the fixture of the smith’s forge, which I had been forced to leave unfinished. Even the short period of work this evening was curtailed by a very heavy shower, which drenched us to the skin—a great evil, where there are many people to be accommodated in a small vessel, without room for much spare clothing, or the means of getting any thing quickly dried. Return to the Rock, and have six days of good weather. After this we had an uninterrupted tract of good weather for six days; and as we landed every morning at four o’clock, and remained on the Rock until eight, taking only half an hour for breakfast, and the same time for dinner, we had thus the work of twenty-eight persons for about ninety hours.

Erection of the Pyramid of the wooden Barrack. After carefully setting out the radial directions in which the six legs, or main beams were to stand, our next step was to lay off their approximate distances from the centre of the Barrack, and to clear a space in the solid Rock of sufficient extent to admit of adjusting the exact positions of the bats before boring the holes. This operation involved the necessity of blasting parts of the Rock by very small shots, the bores being about 1¹⁄₂ inch diameter, and 15 inches in depth, and so directed as to have the effect of throwing off a thin superficial crust without shaking the solid part below. The materials thus quarried in forming the seats for each post were thrown, by means of tackle, into the deepest pools, to prevent their being driven by the sea against the timbers of the barrack, and so injuring them.

No. 4.

No. 5.

Mode of determining the length of the Beams, and the sites for their fixtures. For ascertaining the exact length of each of the six beams, which formed by their union a pyramid of about 21° 30′ of inclination, and, at the same time, for determining its exact place, in reference to the centre of the hexagon, both of which elements necessarily varied with the level of the irregular surface of the Rock, I used the following simple arrangement:—Each beam being of the greatest length that could be required, the level and distance from the centre were ascertained for the longest beam, which, of course, had the lowest seat or rest, by means of a wooden frame, shewn in the diagram ([No. 4]), in which a a is a vertical rod of iron firmly batted into the rock, so as to coincide with the centre of the pyramid to be formed by the main beams, and of sufficient length to exceed the greatest variation of level between the different points where the beams are likely to stand; c c is a horizontal board which can be freely turned about a a horizontally, and resting upon a small shoulder d, and which is equal in length to the radius of the hexagon, on the horizontal plane at the level of the lowest beam. On this board is a spirit-level s, which regulates its horizontality; e e is the approximate position of the lower end of the beam; f f is a pitched board, representing the section of the permanent beam, on a vertical plane passing through the axis of the pyramid, and also shewing its inclination towards the centre of the pyramid. As this pitched board is capable of being moved up or down by sliding through a groove at g, it may be successively applied to the rough surface at e e in the course of cutting it down, and thus be made truly to represent the position of the beam, and, at the same time, give the inclination of the surface e e, which must be at right angles to the axis of the beam f f. In this way, by repeated trials, the surface was truly dressed to its proper inclination, and the length ascertained which required to be cut from the beam, so as to make it rest on that surface when in its true position. Hence, also, in the case of all the other beams, the length which the pitch-board f f was moved upwards through the groove g, beyond the level c c, indicated the quantity to be cut from the end of any given beam.[17] The surface of the Rock, dressed for the seat of the beam, being thus brought to its proper inclination, the sliding-board correctly set and the centre line a a of the beam carefully marked on the Rock, a square board (see [fig. No. 5]) representing the cross section of one of the beams, was then put down at the proper distance, so as to cover the space indicated by the pitch-board as the site of the beam, and with its centre coinciding with the radius already traced on the dressed seat or bed. When so placed, the small round knobs, or ears, d d ([No. 5]) on this board, shewed the position of the holes to be bored for the bats or side fixtures, which, as afterwards shewn in figure ([No. 8], p. 88), spread outwards from the axis of the beam, and thus formed a kind of dovetail. In order to make the holes capable of receiving the bats and, at the same time, embracing the timbers of the barrack, a quoin of wood ([Nos. 6] and [7]) e, was put down, with bevelled faces or grooves g, cut in it for directing the motion of the jumper or boring iron i, thus:—

No. 6.

No. 7.

These holes were bored with jumpers, 3¹⁄₂ inches in diameter, and were sunk 2 feet deep in the rock. The boring of each hole took upwards of eight hours, in consequence of the hardness of the material, which is gneiss, a stone considerably more difficult to bore than even the granite of Aberdeenshire. The bats or stancheons, although very accurately forged, were occasionally found not to fit truly, owing to unavoidable twists in the holes, which arose from dries or veins in the Rock crossing the line of the hole, and thus disturbing the motion of the jumper. This gave us much trouble, and shewed that, had we determined, as I at first contemplated, to cut a lewis-hole, swelling towards the base, the work would have been almost impracticable. The mode which I had proposed for executing this operation was to bore a number of very small holes, inclined at the proper angle, all round the outside of this lewis chamber, and then to cut out between them; but this, as our after experience in cutting the foundation of the Tower proved, would have occupied an extent of time which we should have been very unwilling to bestow upon a merely temporary erection like the wooden barrack. Even as it was, and with all the retrenchments that could be safely adopted, the preparation of the seats for the six outer or main beams, and those for the six inner braces, employed twelve men for four days.

[17] The accented letters e′, c′, f′, g′, o′, s′, in the figure ([No. 4]), page 85, denote the various parts of the gauging-rule, when applied to the beam, opposite that to which the letters e, c, f, g, o, s, in the text, refer.

No. 8.

After the seats for the timbers had been dressed in this manner, the carpenters were employed cutting the beams to their respective lengths, the piece to be cut off being measured, as already stated, by the length through which the sliding-board f f ([No. 4], p. 85) had been raised above its position on the level platform on which the pyramid had been erected in the workyard at Greenock. At the same time, the stancheons (k k) in the figure ([No. 8], p. 88), and the glands or collars e e (in [figure No. 8]), were let into grooves in the beam, and the holes admitting the screwed bolts a a, to pass through the two stancheons and the beam between them, were bored with an auger, and widened with a red hot iron. The tops of the beams b b (see [fig. No. 9]), having been already fitted in the workyard at Greenock, so as to meet a hexagonal quoin of hardwood e, round which they were assembled as shewn in the figure ([No. 9]), straps of iron d d, were made to pass over the top of the whole, and were secured to the beams with bolts, and a spike at a was driven into the centre to wedge the timbers tightly up, so as to fill a ring which embraced the exterior of the whole. It was obvious, that if the sliding-board (described on [p. 85]) had indicated the true inclination of the seat on the Rock for the end of the beam to rest on, as well as its radial distance from the centre of the pyramid and the corresponding length of the beams, the top of each beam must necessarily meet in its exact place around the central hexagonal quoin. The operation of determining the positions and lengths of such beams on a rugged rock, and placing them with the accuracy requisite, to insure their mitering truly at the top, was attended with a good deal of trouble; and I have judged it advisable to give these details, as they may prove useful to others who may have a similar work in hand.

No. 9.

After a good deal of trouble, owing to the lowness of the Rock and the smallness of its surface, the six main beams, each nearly 50 feet long, were raised on end by means of shear-poles, and the iron straps which passed over the top of them, and the ring which embraced the whole so as to secure them at the top, were fixed with much care. The temporary guys were removed on the afternoon of the 18th August. A plummet suspended from the centre of the quoin, after all the six beams were in their places and the stancheons had been run up with lead, came within half-an-inch of the centre bar, which was about 40 feet below the point of suspension, thus indicating an angular deviation of less than 4′. This is a very good approximation, under all the circumstances with which we had to contend; and it is chiefly to be imputed to the very accurate measures pursued in the workyard of the contractor at Greenock, by Mr George Middlemiss, foreman of the carpenters (who then acted as superintendent of the contract works), and whose intelligence and zeal made him, at all times, able and ready to do full justice to all my suggestions for incurring as little loss of time on the Rock as possible. The operation of fixing these six beams, which formed, by their union, a hexagonal pyramid of about 44 feet high, and about 34 feet in diameter at the base, occupied only six days, including the cutting of the seats and the boring of the holes in the Rock. Much labour and time were consumed in the mere moving of beams, each weighing about 13 cwt., over the rugged surface of the Rock, for which purpose we could only use a small set of shear-poles, with crabs and blocks, and tackle purchase; and it sometimes happened, that merely for the purpose of moving a beam, it was necessary to place a special ring-bolt for holding a snatch-block for a few minutes, in spite of all the care and forethought which had been bestowed, in selecting the most advantageous positions for placing them, before the work of raising the beam was begun. Nor was the necessity for securing every loose material by means of lashings to the Rock, before leaving for the night, an insignificant source of delay; for we were sometimes forced by the waves or the darkness, which drove us from our work, to lower a beam which was just ready for being fixed and to replace it in a safe situation.

Pyramid completed. On Saturday the 18th August, the pyramid having been successfully erected, the men were busied for two hours, before embarking for the vessel, in collecting and lashing all the loose materials to the Rock, for the sky gave some indications of a change. As we took to the boats, I looked at the result of our labours with some satisfaction, not unmingled with gratitude.

During the week, while we had been engaged in fitting up the main timbers of the barrack, the weather had been very fine; and except the long hours of toil and the sea-sickness on board the vessel, there was nothing to complain of; Mode of living while erecting the Barrack. but the economy of our life while moored for days off the Rock, was somewhat singular. We landed at four o’clock every morning to commence work, and generally breakfasted on the Rock at eight, at which time the boat arrived with large pitchers of tea, bags of biscuit, and canteens of beef. Breakfast was despatched in half an hour and work again resumed, till about two o’clock, which hour brought the dinner, differing in its materials from breakfast only in the addition of a thick pottage of vegetables, and the substitution of beer for tea. Dinner occupied no longer time than breakfast, and like it, was succeeded by another season of toil, which lasted until eight and sometimes till nine o’clock, when it was so dark that we could scarcely scramble to the boats, and were often glad to avail ourselves of all the assistance we could obtain from an occasional flash of a lantern and from following the voices. Once on the deck of the little tender and the boats hoisted in, the materials of breakfast were again produced under the name of supper; but the heaving of the vessel damped the animation which attended the meals on the Rock, and destroyed the appetite of the men, who, with few exceptions, were so little sea-worthy as to prefer messing on the Rock even during rain, to facing the closeness of the forecastle. As I generally retired to the cabin to write up my notes, when that was practicable, and to wait the arrival of my own refection, I was sometimes considerably amused by the regularity with which the men chose their mess-masters, and the desire which some displayed for the important duties of carving and distributing the rations. Even the short time that could be snatched from the half-hour’s interval at dinner, was generally devoted to a nap; and the amount of hard labour and long exposure to the sun, which could hardly be reckoned at less than 16 hours a-day, prevented much conversation over supper: yet, in many, the love of controversy is so deeply rooted, that I have often, from my small cabin, overheard the political topics of the day, with regard to Church and State, very gravely discussed on deck, over a pipe of tobacco. Perhaps the great heat below, where upwards of twenty people were confined, might in some measure account for this wakefulness on board the Tender.

One beautiful morning, during our stay of six days at the Rock, we had a visit from Shoals of Medusæ seen. a shoal of small fish, whose novel appearance made me take them for a fleet of some species of Nautilus. Those animals came in such numbers, that the pale blue silky membranes or sails, which wafted them before a gentle breeze over the glassy surface of the ocean, literally covered the water as far as we could see. One of those animals I sent in a small phial to my friend, Professor Fleming, then of King’s College, Aberdeen, who assigns to it the Linnean name of Medusa velilla, and says it is noticed by Dr Walker and Mr Pennant, as a native of Scotland.

The threatening of the previous night was fully verified by the succeeding Sunday morning, as a strong southerly wind with heavy showers, forced us to part from our moorings at the Rock at break of day, and make sail for Hynish Bay, where we anchored at seven. On Monday I landed at Hynish; but as the wind, which had increased to a strong gale, was still rising and inclining more to E., Mr Macurich summoned me to the boat, when, with much difficulty, and at the expense of shipping several seas, we reached the vessel which was pitching the bowsprit under. Driven by a gale to Mull. This soon forced us to run for the Sound of Mull, where we were detained until Saturday the 25th, on the morning of which day we again made Hynish Bay; but the wind, which had been less violent when we started from Tobermory the night before, again commencing to blow strong from the same unpropitious quarter, Return to Hynish, and are driven to Coll. we had only time to land at Hynish, and take on board a salted sheep (which proved a rather unpalatable addition to our provisions), when we were forced to seek shelter in our old quarters at Loch Erin in Coll. As we entered Loch Erin, we saw the Regent (the General Lighthouse Tender) leave the Sound of Mull, and again put back to Tobermory. Next day (the 26th August) we left Loch Erin, and boarded the Regent; but the weather proving boisterous, we were again forced into our old anchorage, while the Regent proceeded with the Engineer, who was then on his annual voyage, to Barrahead Lighthouse, without attempting to go near the Skerryvore. From this date the weather did not prove favourable for a landing until the 30th, when the wind being N.W., we sailed from Loch Erin at daybreak, Return to the Rock. and reached the Skerryvore at ten. We now discharged all the remaining materials which had been shipped for the Rock with a view to complete the pyramid of the barrack, which it was intended should stand the test of a winter, deferring the fixing of the habitable part till next spring.

31st August.—The last day of August was one of considerable discomfort. Our landing at four in the morning was attended with great difficulty and some danger; and throughout the day we were a good deal incommoded by a thick drizzling rain, which continued without intermission. About mid-day the sea rose so much as to render it no longer prudent to delay leaving the Rock, and we therefore embarked. After lying at our moorings until half-past two, in what, to landsmen, was a most distressing sea, Driven to Tyree. we slipped and ran for Hynish Bay, which we reached at 5¹⁄₂ P.M. The weather continued boisterous until next evening (1st September), when the wind went round to the north, and at eight all the men were summoned on board; but although we sailed at daybreak, we could not reach the moorings with daylight; Return to the Rock. and it was not till the morning of the 4th September, about four o’clock, that we could again land on the Rock. We succeeded, in spite of a very unfavourable day, in remaining till three o’clock, Horizontal braces fixed. during which time we fixed the whole of the horizontal braces, and got everything which we had not been able to secure in its place firmly lashed to the ring-bolts on the Rock, after which Driven to Mull. we were forced to leave it for Mull. Heavy gale. The gale continued to blow very hard, without any intermission, for some days; and on the 6th, Timber cast on Tyree. some wreck-timber, covered with goose-barnacles, came ashore among the surf at the beach at Hynish, but no trace of its history was ever found, nor did any rumour reach us of a shipwreck having occurred on this coast. It was not till the 8th that we could again attempt to reach the Skerryvore; when, sailing from Mull with a fair wind, and taking on board at Hynish nine masons, and Mr C. Barclay, foreman of the quarriers, we again landed on it at 2¹⁄₂ P.M. Return to Rock, and farther progress of barrack. We succeeded in getting up the mortar gallery (see [Plate V.]), and in fixing some of the diagonal braces, and left the Rock about eight. A marrot perched on the vessel’s side this afternoon, much fatigued and evidently desirous to get on board; but the sailors, from some superstitious dread, would not admit the poor bird.

10th September.—We landed at four o’clock, and had a long and good day’s work until daylight left us. We were now within twenty-four hours at most of completing all that could be expected to be done this season; and it was with no small anxiety that I observed a change of wind from N.E. to S.S.W., accompanied by a fall of the sympiesometer; as in the event of a change of weather at that season, it seemed very uncertain when we might again land, and still more uncertain whether our work, in its incomplete state, could resist the winter’s seas.

11th September.—Last day’s work on Rock this season. This was our last day’s work on the Rock this season. We landed at four o’clock with very great difficulty, and some danger of having our boats swamped; and we were forced, owing to the heavy sea which broke upon it, to leave the Rock at high water; but, about one o’clock, we were enabled to return, as the sea fell a little. By dint of great exertions, we got the last of the diagonal braces fixed, and the bats run up with lead and painted, for their protection against corrosion. We also contrived to remove the greater part of the tools from the Rock, but some we were forced to leave to their fate. To the upper part of the pyramid we lashed a water-tight chest, containing biscuits and a cask of water, Precaution for the benefit of shipwrecked seamen.to serve as a means of support to any shipwrecked mariners who might chance to reach the Rock. I also caused some spars to be lashed at various levels, by way of testing the effects of the sea; but to how little purpose, the sequel will shew. Before leaving the Rock, I climbed to the top of the pyramid, View from top of pyramid. from which I now, for the first time, got a bird’s eye view of the various shoals which the stormy state of the sea so well disclosed; and my elevation above the Rock itself decreased the apparent elevation of the rugged ledge so much, that it seemed to me as if each successive wave must sweep right over its surface, and carry us all before it into the wide Atlantic. So loud was the roaring of the wind among the timbers of the barrack, and so hoarse the clamour of the waves, that I could not hear the voices of the men below; and I, with difficulty, occasionally caught the sharp tinkle of the hammers on the Rock. When I looked back upon the works of the season, upon our difficulties, and, I must add, dangers, and the small result of our exertions—for we had only been 165 hours at work on the Rock between the 7th August and the 11th September—I could see that, in good truth, there were many difficulties before us; but there was also much cause for thankfulness, in the many escapes we had made.

After a somewhat precarious embarkation in the boats, and shipping several seas in our way, we reached the vessel, and immediately set sail with three cheers, rejoicing to have thus concluded our season’s work.

After spending a few days at Hynish in making various arrangements for the operations of the next season, which were to embrace the extension of the pier, the completion of the barracks and the erection of sheds and workshops for carrying on the dressing of the materials for the Lighthouse Tower, I left Tyree with the pleasing belief that the successful termination of our first season’s labours might be taken as an omen of future success. But how uncertain are even the most rational sources of satisfaction which Time can furnish! On the 12th November, I received from Mr Hogben, the clerk and store-keeper at Tyree, the unwelcome intelligence Destruction of the barrack during a gale. that the Barrack-house had been destroyed, as was supposed, by the heavy sea of the 3d November; and as his letters contain all the facts of the case in so far as they could be collected at the time, I cannot do better than quote them at full length:—Letter from Mr Hogben. “Skerryvore Lighthouse Works, Tyree, 5th November 1838.—Dear Sir,—I am extremely sorry to inform you, that the barrack erected on Skerryvore Rock has totally disappeared. It was seen on the 31st of October, when I observed no change in its appearance. On the two following days the weather was showery, with haze, so that the Rock was not seen; and on the 3d it rained almost all day, with strong breezes. In the evening the wind increased to a gale, with a great swell, and an extraordinary high tide. Yesterday (Sunday the 4th) the weather was moderate, but the swell prevented the Rock being seen from the low ground. Mr Scott and Charles Barclay, however, having gone to the top of Ben Hynish, got a momentary glimpse of the Rock through the spray, and both were of opinion that the barrack was gone. This was not credited by the workmen who had been employed at it, but this morning we found it to be the case; the Rock was pretty clearly seen, but no trace of the barrack. From the circumstance of the yard of a large vessel, and also a piece of a boom, having come ashore in the direction of the Rock, we think it is not improbable that some wreck has happened, and that some part of it has been thrown upon the barrack by the force of the sea. Should any opportunity occur for going out to the Rock, we shall take advantage of it, in order to give you farther information on the subject. I remain, &c. (Signed) Wm. S. Hogben.” A subsequent letter from Mr Hogben is of the following tenor:—“Skerryvore Lighthouse Works, Tyree, 10th November 1838.—Dear Sir,—This morning, Charles Barclay, with a boat and four men, went out to the Rock to view the site of the barrack; and, the weather being moderate, he got a good landing. The following is the state in which he found everything:—The whole barrack timbers had been carried away, excepting the long beam next the place where the crab stood which drew up the beams, and about seven feet of the long beam opposite the place where the other crab stood. The former of these beams had fallen in the direction of the highest part of the Rock, and had drawn one of the iron stancheons 16 inches. The latter was all in splinters, with one of the iron stancheons broken, and the other bent. The rest of the stancheons were broken at the point between the round and the flat, and some of them were drawn about 9 inches. The iron hoop which bound the top of the beams was lying at the distance of about the length of the beams to the eastward of the centre of the barrack, having one of its screws broken. Five large wooden knees were remaining, a ladder partly broken, some moulds for taking the angle of the beams, and most of the quarry and masons’ tools. The grindstone was thrown from the top of the Rock into a deep hole on the side next Tyree, a distance of about 12 yards, apparently whole. The smith’s forge had disappeared, and the anvil had been thrown about 8 yards to the N.E. of the place, where it was left; it was brought ashore, along with the hoop which encircled the top of the barrack. The iron posts which supported the bellows were standing. The crab on the S.W. side was thrown from its place to the east side of the site of the barrack, a distance of about 15 or 20 yards, and was dashed to pieces, excepting the axle, handles, pinion, and the trunk of the barrel. The other crab was thrown from its place to the N.E., over a part of the rock 5 or 6 feet high, to a distance of about 6 yards, and was found in a similar state to the former. A stone measuring three-fourths of a ton was found near the seat of one of the beams; it had been thrown up from the hole where it had been deposited while cutting the seats for the barrack timbers. One of the ring-bolts near the top of the Rock to which the chain binding the wood had been made fast, was broken close by the surface of the Rock, and the wood was all gone. The mooring buoy has also disappeared. The barrack was seen from the top of Ben Keen-na-vara, by some men on Saturday, 3d November, so that the succeeding night, which was truly awful, must have done the damage. I may mention, that many of the islanders say that they have not seen such a swell as on that evening for about sixteen years. I am happy to say that no damage has been done to the works on shore here, as on that evening the wind was about S.W., and we are pretty much sheltered from the wind in that direction. The shore on the S.W. side of the island is strewed with sea-weed, which has been carried up far beyond the usual reach of the tide. Hoping that the above information will suffice, I remain, &c. (Signed) “Wm. S. Hogben.”

On the day on which I received this discouraging intelligence, I requested a special meeting of the Committee, for the purpose of deliberating as to the best course to be pursued, when I received instructions to proceed to the Rock, and for that purpose to hire a steamer at Glasgow. Proceed to Skerryvore. I accordingly started that very evening for Skerryvore, with the intention at the same time of removing such of the men from Tyree as were not to be employed during the winter. I left Greenock in the steamer Tobermory, accompanied by Mr Macurich of the Lighthouse tender, at midnight of the 14th November, after some delay in repairing a leak in the boiler, which was discovered in time before starting, and reached Hynish at 11 on the forenoon of the 16th, having got a good passage round the Mull of Kintyre. The weather was, however, in every other respect most unfavourable for the purpose; and having merely touched, in passing Tyree, at the workyard at Hynish, to inquire whether any thing farther had transpired, and to take on board Mr Charles Barclay, who had visited the Rock after the loss of the barrack, we at once proceeded and reached Skerryvore about 4 o’clock in the afternoon. The sea ran very high, and there was not the most remote chance of landing, but, having got into the boat, I approached near enough to the Rock to enable me to survey State in which the Rock was found. the melancholy remains of our labours, which seemed to be in the same state in which they were described by Mr Hogben. The beam which lay back on the inclined ledge still kept its place, having been firmly lashed by Mr Charles Barclay to a ring which was near it when he landed on the 10th November; and I could see the remains of some of the stancheons and of the crabs which the sea had left. After waiting, in the hope of a change in the state of the sea, until it was nearly dark, we again turned towards Tyree, in all the gloom of a stormy night, and depressed by mingled disappointment and sad forebodings, occasioned by the fate of our intended asylum from the waves. Owing to the heavy sea, and a strong gale against us, we hung for a long time off Hynish Point, and did not reach the Bay till midnight. Next morning about 7, we came off Hynish, in order to take in the men who were to go home for the winter. The ground was deeply covered with snow, which made the embarkation of so many persons and so much baggage a tedious and uncomfortable operation; and when we sailed, we experienced all the inconveniences of a strong gale and a heavy sea, with the concomitant of a deck covered with passengers, all very sick and much dispirited. Many of the men, indeed, seemed to be as deeply concerned for the loss we had sustained as I myself was. To add to our difficulties, the vessel, under the care of a native pilot, had touched slightly on a rock off Hynish Point, and gave some indications of leaking. We, however, reached Oban in safety.

No. 10.

Various conjectures were made as to the cause of the destruction of the barrack. Those who saw it erected were so confident of its stability, that they could not avoid connecting its failure with some injury received from the wreck-timber, which had come ashore on the island of Tyree, two days after the supposed date of the accident. In this opinion they were strengthened by the total destruction of the cranes and other objects on the rock, forgetting that the timber of the barrack itself, when once let loose, must of necessity have proved even a more powerful agent of destruction than the driftwood of the wreck. But whatever doubt may exist as to the Cause of the destruction of the barrack. first cause of the injury, there seems good reason to suppose that the dismemberment of the parts of the structure had commenced with the removal of the horizontal braces, and that the beams, having thus more liberty for play and tremor, had gradually shaken loose the fixtures at the top, which consisted of straps c c, passing right over the tops a a, of the beams and b b, the hexagonal quoin of hardwood already noticed at [p. 88], which were secured by means of a central bolt d, and finally girt outside by a ring, e e, as shewn in the annexed woodcut ([No. 10].) The moment this dismemberment occurred, the beams would be free to work their own destruction; and the enormous leverage which they exerted, when dashed to and fro by the breakers, would soon snap the iron stancheons at the base, and throw all loose to the waves. The only remaining beam was that which was supported against a ledge of rock, and which had received the sea from the opposite direction to that in which it was found lying. That beam, however, although firmly lashed to the rock by the men who first visited it after the accident, along with Mr Charles Barclay, also disappeared in the course of the winter. As a proof how severely these beams had been dashed by the waves, I may state, that the only remaining part of a beam which I saw attached to the iron stancheons, when I landed in the following spring, was so thoroughly riven and shaken as to be quite like a bundle of lathwood.

No. 11.

These circumstances by no means shook my belief in the suitableness of the plan adopted for obtaining a temporary dwelling on the rock; but they induced me, as soon as I received authority from the Commissioners, whose confident expectation of final success was not damped by the unhappy issue of our season’s labours, to examine very carefully the whole details of the ties and fastenings.Preparations for a new barrack. In preparing a similar structure for next season, I resolved to strengthen the ties at the top, where I imagined the former failure to have occurred, by adding six strong stancheons a, a ([Plate V.]), one to each beam, with heads passing through a centre-plate (H), which united them in one as a cap and to which they were secured by strong screws and keys. The nature of those fixtures will be more easily understood by a reference to the figures (1) and (2) in [Plate VI.], which shew an elevation and plan of the upper part of the beams. In the elevation only the beams A, B, C, are shewn; but in the plan, all the six beams appear mitering at their heads n, n, to the central beam or tie o, o (see also [Plate V.]), which was introduced to counteract the tendency of the heavy seas that might burst inside the pyramid, and by exerting a powerful force in the vertical direction, might separate the beams at the top. In the [Plate (VI.)], a, a, are strong stancheons of iron attached to the outside of the beams by bolts, and also by collars r, r, attached to ears g, g. These stancheons being bent into the vertical direction and rounded at the top, passed through the malleable iron plate H, which was held down, and, as already stated, bound the beams together by nuts c, c, and wedges b, b. Through a hole in the centre of this plate, a large spike p was driven, which produced an expansion of the central beam, and thus wedged up or tightened all the joints formed by the mitering of the seven timbers. On each of those stancheons, snugs were formed at e, capable of receiving and retaining in its place against any tendency to move upwards, a strong metallic ring g, which was tightly keyed by wedges at k. Additional ties of iron D, E, F, were also provided, which connected the six beams together in pairs. Each end of those ties was attached to the timbers by three spikes; one tie, D, is shewn a little fore-shortened; another, E, is seen only on the end; while the third F, is shewn as cut off at the middle. Lastly, an important change was made, by the substitution of malleable iron for wooden braces (see [Plate V.]) b, b, b, b, in the horizontal direction. Fixtures of this kind held the whole more firmly together; and their construction was such that they might firmly embrace each beam, without requiring any means of attachment beyond wedging tightly up; and thus the entire strength of the timbers was unimpaired by the driving of spikes or bolts. Those braces ([No. 11]), a, a, had, at each end, double knobs, and were pushed up along the beams, until they squeezed the timbers x, x, x between them; plates p, p (having holes in them through which the double knobs of the braces were made to pass), were then put on and keyed and screwed, as shewn in the figure, so that each beam was quite enclosed by fixtures, which were thus independent of spikes or bolts. Thin hardwood wedges were afterwards driven in, wherever they could be inserted between the iron and the timber; and those wedges were “stitched” to the beams with common nails, merely to prevent their dropping downward, after any temporary contraction of the timber from the state of the atmosphere. In all this, I have anticipated what more properly belongs to the works of the season 1839; but I consider it best, for the sake of clearness, to connect this account of the new with the destruction of the old Barrack.

While the operations already described were in progress at the Rock, Works at Hynish. various works were going forward at the workyard in Tyree. About 16 masons, 12 quarriers, and 4 carpenters, were employed in building the barracks for the workmen and in erecting smiths’ and carpenters’ shops. A large room, paved with a stone floor, for drawing out at full size the courses of the Tower and making the moulds for dressing the stones, was also provided; and a platform of squared masonry was set in the workyard, on which the courses were to be laid, before being shipped for the Rock. During the season, the pier had also been carried out 256 feet, to a point 15 feet within the low-water mark. It was also necessary to provide depositories for the security of tools and other implements, as well as a large coal-shed for the supply of the Steamer which was then in the course of being built. It had, as already noticed, been determined that the stores were to be served out at the cost prices of the Greenock market, to be paid for once a month, at the same time that the wages of the men were paid. That arrangement had been carried into effect on a small scale, from the very beginning of the works; but this season it became necessary, owing to the increased number of men, to conduct it on a more extended and systematic plan; and, for that purpose, a person was required to act as storekeeper and clerk. In order also to preserve the provisions from injury by damp and to secure them from the inroads of the needy Celts and from innumerable rats which overrun that part of Tyree, it was found necessary to set apart, as a storehouse, a large room on the second storey of one of the workshops. The chief articles served out in the store were meal, molasses, sugar, coffee, tea, tobacco and butter. The establishment of the store entailed a great deal of trouble, and led to some expense for carriage and packages, as well as to occasional trifling losses in serving out the allowances or from injury sustained in the transport of the goods; but the inhospitable nature of the country, and the remoteness of Tyree from the ordinary steam-boat traffic, made the adoption of some such plan unavoidable. Amongst other inconveniences which attended the store, not the least may be reckoned the frequent importunities, on the part of the native labourers whom we employed, to be permitted to purchase provisions at the workyard; but that was never acceded to, except in cases where dearths (which are of frequent occurrence in the island) rendered the call irresistible. Had their entreaties easily prevailed, we should soon have had the whole population of Tyree as our regular customers at the Store.

Hynish Quarries. The quarries at Hynish, as already stated, were by no means productive. The great proportion of the materials which had been quarried, was found to be applicable only to the building of the pier and the inclosing walls, and to the various erections in the workyard; and not more than one-tenth of the whole could be dressed as blocks for the Tower.

During the numerous occasions on which I had been driven by stress of weather to the neighbouring coasts, I had visited the quarries around Oban and in various parts of Morven and Mull. When so forced to leave what I might more especially call my post, I had an opportunity of seeing the quarries at Ardentallen near Oban, which contain the old red sandstone strongly impregnated with clay. That stone is by no means suitable for the face-work of a marine building, in such a situation as the Skerryvore; while the comparatively small quantity of hearting which could be admitted into such a work, made it inexpedient to seek such materials at so great a distance. In this way, the Ardentallen quarry seemed completely excluded from the field. At another time, in passing through Inverary, I devoted a day to the examination of the quarries which had lately been opened at that place and in which a beautiful porphyry is wrought; but I saw no appearance of very large blocks, or, at all events, nothing that could favour the expectation of a considerable supply. But after carefully weighing the matter, the great masses of granite at the Ross of Mull finally determined my choice in favour of that locality; and the Duke of Argyll having, with the greatest liberality, ratified his predecessor’s grant of liberty to the Lighthouse Board to quarry stones from any part of the Argyll estates, it was resolved to take measures early in the spring of 1839 for opening quarries at North Bay, in Mull, where an excellent station for shipping had been discovered, close to the place where we saw the most promising appearance of rock. This measure seemed the more indispensable, as the last part of the quarry terred[18] or laid bare at Hynish, had greatly disappointed our expectations. The unworkable nature of gneiss rock also and its extreme uncertainty with regard to quality, farther concurred to make a change most desirable. Granite, indeed, is a material in many respects superior to sandstone, gneiss, or porphyry. The first it greatly excels in durability and weight; and, as a stone for the workyard, it is superior to the other two, from its property of being fissile, or easily split in any direction. In this respect it resembles certain parts of some sandstone strata which are commonly called liver rock, of which Craigleith quarry, near Edinburgh, furnishes an excellent example. Porphyry, and, I think, all other igneous rocks (excepting granite), gneiss also, and most of the other primary rocks, have not this property, being fissile only in one plane, so that quarries of those rocks generally turn out very uncouth or irregular stones, which, though they may in some favourable cases possess good natural beds, will always be found to have ragged and irregular joints, which, for the most part, are incapable of being properly dressed.

[18] This term in Scotland denotes the removal of the soil and unsolid material, in order to lay bare the rock previous to working the quarry, and seems obviously to be derived from the Latin “terra,” perhaps through the medium of some old charter. The quantity of terring very much affects the profitable working of a quarry.

CHAPTER V.
OPERATIONS OF 1839.

During the winter months which intervened between November 1838 and March 1839, a small detachment of men, consisting of three masons, nine quarriers, and one smith, were left at Hynish under the superintendence of Mr Charles Barclay, to clear the landing-place of several patches of rock which encumbered the entrance. Shipping Station and Pier at Hynish. They were also to build some walls of inclosure, and to quarry and dress stones for the pier and other buildings at Hynish. The provision of accommodation for shipping at that place was now naturally regarded as of more urgent necessity than formerly, because the importation of stones from Mull, which the failure of the Tyree stone had rendered unavoidable, led to the necessity of a reshipment of all the materials at Hynish, where they were dressed before being sent to the Rock. It may, perhaps, be naturally enough imagined, that instead of importing the materials to be dressed at Tyree and there reshipped in order to be carried to the Rock, they might have been prepared in Mull, and sent directly to the Skerryvore; but many things concurred to render this inexpedient, if not altogether impracticable. The advantage of being able, by means of a good telescope, in some measure to ascertain the state of the sea at the Rock, the comparative shortness of the passage, which gave the prospect of several cargoes being landed on it in one day during fine weather, and the convenience of communicating with the Rock by signal, were circumstances in themselves quite sufficient to determine my choice in favour of Hynish, as the place from which the materials must be shipped for the Rock, even if there had been no other considerations leading to the same conclusion. But in addition to all this, I could not fail to perceive that Hynish was the only place for the permanent station of the vessel attending on the future Lighthouse; and that on that account alone the construction of a Harbour there was unavoidable. That the arrangement, by which the future station for the Tender was used as the workyard for the operations, was the most judicious that could have been adopted, was fully proved by my subsequent experience of the advantage of assembling all our materials and all our force at a point as near to the Rock as possible, so that we might be at all times ready to supply defects or omissions, and take advantage of every favourable change of the sea or sky.

In the middle of March the Regent conveyed from Aberdeen a detachment of twenty-nine masons and quarriers and five smiths, and the foreman of the workyard, who, together with the men already at Hynish and the native labourers, were to be employed during the season of 1839, in the various departments of the work. On their arrival the men were separated into two small bands, of which the one, consisting of six masons, twelve quarriers, one smith and a foreman, was stationed at North Bay in Mull, where the new quarries were to be opened; while the other had its head quarters at Hynish, and, when not engaged in the work on the Rock itself, was subdivided into smaller parties, varying in number with the nature of the particular operations in which the men were occupied.

On the afternoon of the 19th April I sailed from Greenock in the Regent, for North Bay in Mull, Granite quarries in Mull. where the quarries were to be opened. We had on board the whole materials of the new Barrack, which was to supply the place of that which had been destroyed in the preceding month of November; and we had also a party of carpenters who came to fit up the Barrack in a temporary manner at North Bay, as a residence for the masons who were to be engaged in preparing more permanent dwellings for the quarriers and in forming a landing-wharf for the shipment of the stones for Tyree. It was not till the 25th, after a tedious passage of six days, that we anchored at North Bay; and next morning we had the satisfaction of seeing the steamer, the Skerryvore (by which name she was specially set apart for the service of the works), arrive in the Bay with a party of masons and quarriers, who had been appointed to meet us in order to begin the work.

The necessary arrangements with the Duke of Argyll’s tenants at the Ross of Mull (in which district North Bay is situated) having been already made, no time was lost in erecting the wooden Barrack; and, in seven days after our arrival, the masons and quarriers entered their new habitation under the charge of Mr Charles Stewart, whom I left as foreman of the North Bay works. Mr Stewart and his party, following the example of diligence thus set to them, were not less expeditious in proceeding with the work which had been assigned to them; and by the beginning of August a range of barracks, capable of accommodating forty persons, had been erected, a landing wharf had been built, and various storehouses had been provided, although the quarry had to be opened, and the blocks of stone required for those various works were still in situ at the time of our landing at North Bay three months before.

The landing wharf is placed on a small projecting face of rock in a depth of 12 feet at high water of ordinary spring tides. It presents a face of 40 feet in length, and was provided with wooden fenders for the protection of the vessels loading stones. Landward of it a considerable space was levelled, by cutting and filling, to serve as a yard for storing the quarried materials, so as to be ready for shipment. The quarry itself was opened in the face of a hill, so steep as almost to deserve the name of a cliff; but advantage was taken of a deep gully which intersected it and in it an inclined plane was formed communicating directly with the landing-place. This gully was partly cleared by excavation of the rock and partly, where necessary, its inequalities were smoothed down by filling it with stone shivers; and along its bed thus prepared, longitudinal sleepers of timber were laid, to which edge-rails were attached.

At the top of the incline two iron drums or barrels were set, and round them were wound, in opposite directions, the chains by which the trucks or wagons, loaded with stones from the quarry, were lowered to the wharf below. A powerful break apparatus was attached to those barrels, to check the velocity of the descending wagons, which was also in part counteracted, by making their gravity act as a power to raise the empty wagons in the same manner as is usually practised in coal-mines.

The quarry itself, as already stated, was opened in the face of the cliff, at a point where the successive beds of solid rock seemed to promise the fairest prospect of success. The preliminary operation was to remove a very thin alluvial cover which scarcely concealed from view a large mass of most beautiful granite, whose reddish colour is said to have given the name of Ross[19] to that part of Mull, the shores of which everywhere exhibit massive slopes of that fine rock. The granite is separated very abruptly from the basalts of the surrounding district, so as to leave the Ross purely granitic; but in no part of the whole coast, which abounds with creeks and bays, does the rock appear to be of equal quality, or so conveniently situated for shipping, and so easily accessible to quarriers, as at the spot we had chosen. I know of no instance of a quarry so fully answering the most sanguine expectations as that of the Ross of Mull; and I have never seen a granite quarry of equally great resources, as regards both the quantity and the quality of the material produced. The rock in general yielded easily before well-directed shots, and was separated into large masses, capable of being advantageously cut, with little loss of material, into shapely blocks, by means of wedges, which work remarkably well in that rock. A few weeks after the quarrying operations had been commenced, a single shot detached 150 tons of excellent stone, in the cutting of which into blocks for the Lighthouse Tower little loss of material occurred; and in the course of the season of 1839, although the summer was chiefly spent in the preliminary works above noticed, the Mull quarries produced nearly as much workable material for the Lighthouse Tower as the Hynish quarries had done in three years. In the course of the future working of the quarry, when it came to be more fully opened, its resources were so great, that on one occasion a single shot shook about 570 tons, while another shot detached a mass of 460 tons. In that way, between April 1839 and June 1840, material had been quarried in that single spot, sufficient to supply 4300 selected blocks, varying in weight from ³⁄₄ ton to 2¹⁄₂ tons each. The average monthly produce of the quarries was about 400 tons, and there were generally employed in them 26 quarriers, 3 labourers, and 2 smiths. The quantity of gunpowder consumed in the quarry was small, as it was almost exclusively employed in great bores about 11 feet deep, for the purpose of detaching large masses which had no open side and could not be removed by means of the pinch or crow-bar. When a mass of rock had been thus removed, it was cut up into various portions by means of wedges, and finally subdivided into blocks, hammer (or as it is called quarry) dressed, according to rough moulds, whose dimensions exceeded those of the stones of the various courses of the building by a quantity which was considered sufficient to cover any casualty in the final dressing of the block by the masons at Hynish, and which allowance was generally equal to a film of rock about 1¹⁄₂ inch in depth. The blocks thus roughly formed were shipped for Hynish, distant about 26 miles, through a tempestuous sea, open to the full reach of the Atlantic towards the south-west, sometimes in a small vessel called the “Queen,” belonging to the Commissioners, and sometimes in undecked boats of 16 tons, belonging to the adventurous men of Tyree. The freight usually paid was 5s. a ton, and yet the whole of the blocks for the Lighthouse Tower, and many of those used in the pier at Hynish, were laid down to the number of about 5000, at the rate of 2s. 1¹⁄₂d. per cubic foot, including all the expense of building barracks, opening quarries, freight of stones, and the expense of building and maintaining the small vessel called the “Queen,” above noticed. The stone of the Mull quarries is a reddish or flesh-coloured granite, in which felspar predominates. About 13·66 cubic feet weigh a ton, and it is not quite so hard as the granite of Aberdeen.

[19] Whether from any inflection of the Celtic Rhua, or Roy, or directly from the Italian Rosso, it would, perhaps, be impossible to determine.

As I am not aware that any professional work contains a detailed description of the quarrying of granite, some observations on that subject may not be unacceptable in this place; Observations on the quarrying of granite. and I therefore propose, at the risk of appearing somewhat prolix, to give a pretty minute account of the mode of opening and working a granite quarry, more especially as practised by us at North Bay.

Having laid bare the rock of earth, gravel, or other loose matter (which operation, as I have elsewhere mentioned, is in Scotland technically called terring), and having swept or washed clean the surface of the rock so as to have a good view of the natural seams or joints which traverse it, the next step is to fix the best place for putting in a bore or mine.

In selecting the position of the bore, the direction of the seams and veins of the rock must be duly considered, with a view to employ the force of the explosion to the greatest advantage in separating the natural joints or beds of the rock, instead of shattering the solid masses or posts (as they are called in the language of the quarry) into shivers or fragments.

One thing to be strictly borne in mind is, that the bore should never be in the centre of a fine or large block, but should be placed within a few inches of its back so as not to break the finer rock into small and useless fragments; and care must, at the same time, be taken to keep the bore clear of cracked or unsound rock, as the jumper, in passing through such material, is liable to be jammed by the cracks and fissures before it can be driven to the proposed depth. It is not possible to lay down precise rules for guiding the quarrier in choosing the place of the bore, as his plan must be regulated chiefly by the circumstances of each case; but it may be observed, that having first determined the depth of the hole, it will seldom be found advantageous to keep the bore farther back from the face of the rock than about four-fifths of that depth. The depth itself, also, to which the mine should be carried, is a point for deliberation with the skilful and experienced quarrier, who will take great care not to go so deep as to pass through the solid rock in which he is boring and thus to touch a bed, unless indeed he shall think it advisable to attempt to raise more than one post of rock by a single mine, in which case he will carry the bore through the first post into the second or third as the case may be. But in all cases the boring must be stopt at two inches before coming to the bed or seam of the post in which the mine is to terminate, lest the exploding powder should escape by the bottom of the bore, and thus leave the top of the rock altogether undisturbed. In endeavouring to procure large materials, the bores should in general be as deep as possible. It is only experience, however, which teaches the quarrier to form a sound prognosis as to the direction and level of the beds of the rock at any particular spot, and enables him to choose the most advantageous position and depth for the mines.

In the blasting of granite there are a few general rules which (although it may not be necessary to follow them in every case) may be considered as constituting the best practice. If the bore be a vertical one of the depth of 6 feet, 2¹⁄₂ inches diameter at the top, diminishing to 2 inches at the bottom, may be considered a proportionate caliber. If the bore be a deep one (perhaps of 14 feet), its diameter will require to be 3¹⁄₂ inches at the top, and should diminish to 2³⁄₄ inches at the bottom; and the quantity of powder required for the charge will in most cases be about as much as is required to fill ²⁄₅ths of the hole.[20]

[20] Miners and quarriers, who always work by empirical rules, disregard entirely the line of least resistance as a measure for the charge, and invariably refer to the depth of the bore.

The patent fusee having been inserted among the powder, with its end about the centre of the charge, and the upper part of the bore having been filled up with dried clay, well forced down with a wooden rammer faced with copper, a length of 3 or 4 inches of the fusee should be left outside the bore, to which the match is to be attached. Having cleared away every thing near the blast which can receive any injury and covered up the machinery of the cranes with strong planks, the mine may be said to be ready for being fired; and, on a signal given, by blowing a horn, all hands retreat to a safe distance, with the exception of the fireman, who then lights the match, and follows the others as fast as possible.

If, as already stated, the object in quarrying be to obtain large materials, the bores should, if possible, be deep; and, in that case, the rock will seldom be thrown down in fragments by the blast, but will merely be cracked, and intersected by rents about one inch in width. Recourse must therefore be had to what, in quarry language, is called a Bull, which consists in running a quantity of loose powder into the crack which has been made by the blast, at that part where its explosion seems most likely to throw out the cracked or broken mass in various fragments and disengage them from their place in the rock. In bulling, perhaps twice as much powder as was used in the bore is loosely poured into the crack, care being at the same time taken to get as much of it to go under the bottom of the rock as possible. After enough of powder has been poured into the crack, a quantity of dried smithy ashes, or dry sand, is run in over the powder, so as completely to cover it, except so much as is required to fire it by; and that coating, which is merely superficial, is employed partly to keep down the powder, and partly for security against its being accidentally fired before all things are ready. The fireman having seen every thing cleared away, gives notice to sound the alarm, when all hands escape to a distance in the direction which is supposed to be the safest. The match is then applied, and the fireman retires, as fast and as far as he can, yet so as if possible to keep in view, during his retreat, the progress of the match. The operation of bulling is far more dangerous than the firing of a bore, as the charge is much greater, and not so well confined, so that many splinters are thrown off, and the direction in which they fly varies continually with the direction of the cracks which the original bore may have produced. As might be expected, by far the greater part of the accidents which occur to firemen in granite quarries, arise from that practice.

No. 12

Should it happen, as it sometimes does, that after having gone through those operations, the quarrier fails in getting the cracked mass thrown down to the bottom of the quarry, he varies his mode of attack, and proceeds to bore a row of plug-holes on the face of the rock in such a line as to cut off a part from one end of the shaken mass; and for that purpose he is often obliged to hang a scaffold over the face of the rock on which to stand while boring the holes. Those plug-holes should be slightly inclined, so that, when the wedges, called plugs[21] and feathers, are driven into them, they may rend the rock in such a direction that the piece intended to be cut off may be a little narrower on the inner than the outer face, so that, thus resting on an incline it may be more easily taken out. The plug-holes should be cut at one foot asunder, and bored with a jumper 1¹⁄₂ inch diameter to the depth of 9 inches; and if the plug-holes be deep, and some difficulty in driving be expected, the plugs should be carefully greased or oiled previously to being driven. Having cut off a block as above described, an attempt may be made, if the mass be great, to throw it down by means of bulling; but if it be of lesser dimensions, and there be reason to expect that it may be removed in the ordinary way, the power of the crane may be applied to draw it down. For that purpose, the quarrier employs an instrument called a Dog, which is a strong short hook, armed like a pick on the point with steel, and having a ring in the end of it for the hook of the crane-chain to pass through. Having cut a small hole with a pick, on the upper part of the block which is meant to be removed, the steeled point of the dog is inserted into it, in such a manner that the weight of the crane-chain may retain it steadily in its place. Five or six men then heave on the crane a strain just as much as they suppose it may bear, without danger of carrying away any of its fixtures; and as many men as can find room are, at the same time, employed at the top of the rock, working with crow-bars behind the block, so as to shake it and loosen its hold. The two parties continue their work reciprocally, leading and following,—the men at the crane, still keeping up the strain, and taking care not to heave so much as to break any of the chains, while those on the top continue to shake the block by means of the crow-bars, or throw in stones into the opening, which is always getting wider between the block and the cliff, so as to prevent the loosened mass from falling back into its old place. When the block has been drawn as far forward as to appear just ready to fall over the cliff, one of the most expert men at the crane stands carefully watching the movement of the block; and whenever the stone begins to fall, he instantly throws the crane out of the gear, so as to prevent the wheelwork being pulled to pieces by the tumbling mass getting entangled in the chains, on which it frequently falls and breaks them to pieces. The operation of taking down large blocks from a great height is very tedious, and is often attended with much danger, as the stone, when it falls on the bottom of the quarries, makes the shivers among which it alights fly in all directions with a force which nothing can withstand.

[21] The plug ([fig. 12], c c′), and feathers ([fig. 12], d d′), are flat pieces of malleable iron, slightly tapered, and forming together a kind of compound wedge, the two feathers being first inserted into the hole, and the plug being driven between them by a series of gentle blows, from malls of the weight of from 30 lb. to 35 lb.

An opening being made in the manner above described, by getting one piece brought down, the same process is continued by cutting off and taking down pieces of eight or ten tons weight, until there be as many blocks in the floor of the quarry as can be easily managed at one time. Those masses are then arranged by means of the crane in convenient positions for being cut up into blocks of the requisite sizes; and as all of them are within range of the crane, they can with its assistance be easily turned over or set in any position. While some of the men are employed in cutting up those blocks, others are clearing away the rubbish, and others are boring holes or making ready for a fresh blast.

No. 13.

If those blocks, which we have supposed to be brought down to the quarry floor and to be ready for cutting, exceed seven feet in depth of cut, their farther subdivision will require the use of the plugs and feathers already described; but if their depth or thickness fall short of that, the ordinary iron wedges will answer. If the cut be of the depth of about 6 feet, the wedges must be placed about 3 inches apart from side to side; but if the depth of cut be less, they may be set 4 or 5 inches asunder. The method of setting in those wedges is as follows:—The person who cuts the wedge-holes generally works in a sitting posture, and if the block will admit of it, he prefers to bestride it, with a stone, as a stool, under each foot. He works with a pick of 16 lb. weight, having a handle only 16 inches long, with which he cuts the first hole generally about 3 inches from the end of the block. The holes are for the most part about 2¹⁄₂ inches deep, and 3¹⁄₂ inches long, and must be well cleared out at the bottom with a sharp pick; and the wedges must be set in a line as fair and straight as possible. Cutting wedges of that kind are of iron, from 7 to 9 inches long, and 2¹⁄₂ inches broad, and weigh about 7 lb. weight each. When in good order they must not be sharp in the mouth, but about ³⁄₈ of an inch thick, to prevent their grounding in the bottom of the hole; for if they but touch the bottom of the hole, they fly out at the first touch of the mall. When the wedges have been all properly arranged for a cut, the workman proceeds to give each of them in succession a gentle tap, so as to make them all fast; and for that purpose he uses a mall about 30 lb. weight ([fig. No. 13]), and having a handle 2 feet 9 inches long. He then goes over all the wedges, giving each of them a smart blow in regular, yet not too rapid succession, but allowing a little time for the parts of the stone to separate gradually. If the wedges be forced too quickly, there is great danger of the cut being spoiled by its flying out obliquely at one side, and thus not reaching throughout the whole depth of the block. The blocks, when thus subdivided by means of the wedges, are generally nearly of the size required by the rough moulds sent from the workyard, and are fit to be carried to the stone-cutter’s shed.

Fig. 14.

As a conclusion to the above account of quarrying, it may perhaps be thought desirable to give some notion of the probable time required to perform certain parts of that sort of work. In boring holes of 1 inch to 1¹⁄₄ inch in diameter, it may be observed that they are generally done with the hand mall ([fig. No. 14]), one and the same person striking with the mall with one hand, and turning the boring tool for himself with the other; and in most cases a man will bore 9 or 10 inches an hour in granite rock. If the bore be 1¹⁄₂ inch diameter, as for plugs, three men will generally bore two plug holes in one hour, each hole being about 9 inches deep. If the bore be for blasting and of 2 or 2¹⁄₂ inches diameter, three men will bore, at the rate of one foot per hour, to the depth of 6 or 7 feet; but if the bore be for a large blast of 13 or 14 feet deep, the hole must be 3¹⁄₂ inches in diameter at the top (diminishing to 2³⁄₄ inches at bottom), and will employ three men working hard between two and three days. Bores of that sort, indeed, cannot be made (at least by hand) to a greater depth than 14 or 15 feet, as the weight of a rod of iron, 17 feet in length, and 2 inches in diameter, makes it quite unmanageable for one man either to turn or to lift; while, from its great mass, the strokes of the mall produce little effect on it. The malls used in boring holes, which require three men, are 7 or 8 lb. weight, having handles 3 feet long (fig. No. 15), and are swung over the shoulder, while striking for down bores, in the same manner as a smith’s forehammer is used. An expert cutter with the wedges will make good wages by cutting holes at the rate of 2¹⁄₂d. for a dozen of holes, taking light and heavy cuts as they come to hand.

No. 15.

What has been said above of boring and blasting refers only to downright or vertical bores; but, in the lower parts of a quarry, it is often necessary to have recourse to what are called breast-bores, from their running in a nearly horizontal direction and piercing the front or breast of the rock. Those bores are not so easily made as the downright bores and, in general, are only used where the rock is low, or in taking up bottom rock. They can seldom be carried to a greater depth than about 9 or 10 feet, owing to the difficulty of turning the jumper, and can never be bored quite horizontally, but require as much dip as will retain a little water in the hole to keep the jumper moving. Instead of throwing the mass outward, as is done by down-bores, those breast-bores generally only cut or break the stone in the direction or line of the bore, so that the block always requires to be afterwards removed by bulling, in the manner already described.

Dressing of the Lighthouse blocks. The dressing of the blocks for the Lighthouse Tower, as already mentioned, was one of the most important operations in the workyard at Hynish; and as no writer with whom I am acquainted has given any account of the mode now practised of dressing granite, I hope I shall be excused for attempting, in this place, to give some idea of the method employed by the masons of Aberdeenshire, whose skill in that department of workmanship is well known both in our own and in other countries. As the whole of the materials for the Tower were to be dressed in such a manner as to avoid the necessity of any fitting on the Rock, by the introduction of what are technically called closers, the greatest accuracy in the formation of the moulds from which the stones were to be shaped became necessary. With that view, I had a trainer or radius made with a moveable vernier, capable of sliding along it, so as to give the differences between the readings of the feet, as far as to the thirtieth part of an inch; and I was thus enabled to lay off the batter or slope on each course (according to the quantities in the [Table of Co-ordinates] in the [Appendix]) with great nicety, and so to trace very distinctly the contour of the intended column.[22] On the stone floor of an apartment in one of the workshops, the quadrant of each course of the building was carefully drawn out, at full size, and divided into the sectors which were required for preserving a due bond among the joints of the adjoining courses. The form of each stone in the tower having been thus determined by those full-sized draughts, moulds, representing the beds and sides of each stone, were prepared according to them, of seasoned timber, well shielded at the angles with sheet-iron, to prevent their being injured. Those moulds having been marked with reference to the number of the course, and the position of the stones in the wall, were given to the foreman of the workyard, who regulated the work of each of the stone-cutters, often to the number of 70 men. A proper block having been selected for each stone, leaving about 1¹⁄₂ inch all round the extremity of the moulds when applied to its several faces, it was conveyed, by means of the sling-cart, to the shed where it was to be dressed. The shed for dressing granite stones differs in no respect from an ordinary mason’s shed, except in its greater height; but, as the stone cutter, in order to wield his tools to advantage, must, at certain parts of the work, stand on the top of the block, it has been found, that a height of about 15 feet is required for the back-wall of a granite mason’s shed. Each man also requires, for large blocks, a space of about 10 feet (measured along the front of the shed), as his peculiar territory.

[22] Such nicety, I would observe, was by no means superfluous, because the arrangements of the Tower precluded the possibility of using a trainer in building; and as the whole was done by means of plumb-templets, the greatest accuracy in tracing the curve of the Tower became necessary, as the only true basis of good workmanship on the Rock.

When a block has been brought to the shed, the first thing to be done, if it is a large stone of 1¹⁄₂ or 2 tons weight, is to lay it nearly level on the ground, with the side which is to be first dressed uppermost. The form or plan is then sketched upon it according to the mould, and the stone is blocked out with a large hammer weighing 30 or 35 lb. ([fig. No. 16]), which is the most suitable weight for ordinary men, although a stout man will manage one of 40 lb. well enough, if the block be lying in an advantageous position. When the stone has been thus rudely blocked out, it is set upon its edge with a gentle inclination to one side, so that the mason, who mounts on the top of it, may conveniently use a pick of 18 lb. weight, having a handle three feet long, to dress off very roughly the most prominent parts of its irregular surface. In doing that he makes a great many deep ruts in a downward direction, at the same time taking care that none of them shall be so deep as to fall below the general surface of the stone when finished. When he has in that style dressed as far down the surface of the stone as he can conveniently reach, (and that is generally about half way,) the stone is then thrown over and set up on the opposite edge, when he again mounts upon it, and goes over the rest of the surface in the same manner, until the whole shall be reduced to one rough plane, so that in spite of numerous partial inequalities, the general face may be straight, or what is technically termed out of winding. A stone in that state is also said to be well opened.

No. 16.

No. 17.

No. 18.

The next step is to raise the stone so that it may incline at about 30° or 40° with the horizon; after which the mason, standing at the higher side, commences to put on the draughts or guide-lines all round the edge of the face which he has just opened. For that purpose he first employs a pick of about 12 lb. weight, having a handle about 2 feet in length ([fig. No. 17]), with which he dresses a band of about 3 inches broad, taking care that this band or draught be straight and out of winding. He then, with the pick, goes over the whole face between the draughts, dressing off all the ridges which still remain between the ruts which he had made while the stone was standing on edge, as before noticed, so that the whole surface will present the appearance of a pretty regularly dabbed face. Having arrived at that stage, he next proceeds to put on the true draughts (as round the edges of the stone, as in the case of the guide-lines), with the cast-steel chisel or punch (a, a′, [fig. No. 18]), and a small iron-mall of 3¹⁄₂ lb. weight; and afterwards with the axe, he carefully axes a band about 2¹⁄₂ inches broad, so as to be quite out of winding, and as straight as possible all round. The dressing is then completed between those bands. If the block be a broad one, the mason will probably be able to take in only one half of the face at a time; and, in that case, the stone must be let down at the high side, and the other one raised as high as may be necessary to enable him to work to advantage. If the surface thus dressed, which is in this case supposed to be the largest side, be intended for the bed of a stone, the knobs or high points between the pick-dabs are merely roughly dressed down with a blunt axe, so as to be all as low as the axed lines or draughts round the extremities, and thus to present no convexity on which the stone, when laid, could rock; but if the surface should be meant for a fine face, the dressing must be commenced with a bluntish axe, taking care that all the axe marks be made quite across the stone, at right angles to the side where the workman stands. The whole face having been once gone over in that manner with a blunt axe, a sharper and well ground axe is next used for crossing the first axing in such a manner that all the second axe-marks may be inclined at an angle of 45°, or thereby, with the first. The whole face having been thus brought to a smoother and more uniform surface, the third and last axing follows; and then the mason uses his shortest and lightest axe, which must, for that work, be well ground and sharp. That axing must be done right across the block, or in the same direction as the first axing had been done, and in that state the surface of the stone may be supposed to be fine enough for most kinds of work used in housebuilding or in public works; but for very fine work, such as some sepulchral monuments, or for surfaces which are afterwards to be polished, it is not unusual to axe four or even five times, care being always taken that how often soever that operation may be performed, the axing should never be made twice consecutively in the same direction, for by that precaution alone can a true and even surface be obtained. (The form of the axe is shewn in [fig. No. 19].)

No. 19.

No. 20.

The dressing of the first face being finished in the manner described, the block is laid flat on the ground, and the plan or form of the stone is then accurately drawn on it, according to the mould, with some substance that makes a bright or good mark, such as a piece of tile ground sharp, or a thin splinter of logwood. If there be much waste to be taken off beyond the lines so drawn, a hammer, whose weight must be in proportion to the piece to be struck off, is applied; but care must be taken not to come too near the lines with the hammer, and it is generally safe to leave at least an inch outside of them. The piece which is left gives a good hold for the chipper or pincher ([fig. No. 20]), which is next carefully applied along the line, being steadily held within one hand, and with the other sharply struck with a small iron mall of 3¹⁄₂ lb. weight, having a short handle about 8 inches in length. While the chipper receives sharp strokes in succession with the mall, it must be slowly moved several times along the line from one end of the stone to the other, till the piece projecting beyond the line, or a part of it, breaks off. Such is the power of this small instrument, that it not infrequently cuts down to a depth of 9 or even 12 inches, thereby doing more execution and to greater purpose, than a heavy hammer can generally accomplish, even in the hands of a skilful workman. The chipper is a tool lately introduced; but has now become a most important article in every hewer’s kit. It makes a regular and clean cut, and leaves little to be done by the punches and chisels ([fig. No. 18], in p. 122), in preparing the arris of the next face of the stone. The block is now raised a little from the ground, and the workman standing at its higher side, the axing of which he has just finished, puts on with the punches and chisel a fine band or draught along the side next to that just dressed. He then applies to the finished face the square or bevel, according to the inclination of the faces, and dresses a band across the stone at each end of the block; and, finally, joins those two cross bands by means of another band along the back. In that way the external draughts on the second side are completed. He then with the pick and axe dresses away the material between those draughts until the second face is finished; and the same process is repeated for each side of the block which requires to be dressed. If the block be a large one, and it require to be dressed on all its sides, it will, lastly, be cut to the proper thickness or height, which is regulated by means of a gauge, known, in the technical language of the shed, as “a grippers” ([fig. No. 21]),[23] from its embracing the stone on three sides. It is simply a three-sided iron templet, having one long and one short tail (at right angles to the connecting piece), the space between the two tails shewing the thickness of the stone.

[23] The figure shews “a grippers” for a stone 14 inches thick.

No. 21.

The practical reader will readily see, that what has been said above about the hewing of granite, is chiefly applicable to the dressing of the large stones used in public works, such as docks, bridges, or marine towers; and it may be proper to add, that such heavy materials are always dressed on the ground, and that a piece of wood is placed under each end of the stone as a necessary precaution to prevent its being split by the blows of the mall. In dressing the lighter materials for house building, where a good deal of fine work is generally required, the stones are laid on what is called a banker, similar to that which is used in hewing freestone. The banker is a bench of stone 2¹⁄₂ or 3 feet long, and 2 feet broad, and is raised about 2 feet above the ground, so as to suit the workman’s convenience.

In dressing one of the outside stones of the first or lowest courses of the Skerryvore Tower, a mason was occupied eighty-five hours (see Plans of courses, [Plate VIII.]); and in dressing one of the largest of the hearting or inner stones of the same courses, fifty-five hours. But as the work proceeded, owing to the greater readiness which the men had acquired in the application of the moulds, gauges and bevels, the time occupied, gradually decreased to the extent of about ten hours for each stone, until the work had been carried on as far as to the thirteenth course, where the number of outside stones was reduced to twenty-four, at which stage of the work, the time required for dressing increased to about one hundred and twenty hours for each outside stone. From that point upwards, the time again gradually decreased till we reached the sixty-fourth course, where it may be stated, that, on an average, a man was employed sixty-three hours in dressing each stone; but the time gained in the last instance seemed to depend less on the readier application of the implements, than on the gradual diminution in the size of the stones, which, from that level upwards, decreased along with the thickness of the wall. But above the sixty-fourth course, a very marked increase in the time of dressing took place, owing to the introduction of the ribband or ring joggles (shewn in the Plans of the 84th and 94th courses, [Plate VIII.]); and to the substitution of the dovetailed joggles in the place of the square or diamond joggles, which were used in the lower parts of the building. The time required for dressing a stone of the sixty-fifth course was ninety-three hours of one man, a circumstance which strikingly shews, that a small, and, apparently, trifling alteration in the style of workmanship may sometimes increase to a considerable extent, the expense of a great work. Each radiating stone of the eighty-fourth course, which forms the floor that goes quite through the wall, required one hundred and sixty-one hours for its completion; and the other radiating floor-stones, which did not pass quite through the wall to the outside, occupied one man about one hundred and twenty hours. Each centre stone of the floors into which the others were dovetailed, required about three hundred and twenty hours of one man’s time. The time of a labourer occupied in cutting a hole for the dovetailed Lewis bats, by which the stones were raised, was about three hours.

The tools necessary fully to equip a granite mason are as follows:—One dressing hammer about 16 or 18 lb. weight; 6 dressing picks, from 12 to 20 lb. weight; one small hand-mall, or mash-hammer, about 4 lb. weight; 3 stone axes about 7 lb.; 16 or 18 cast-steel punches and chisels, with one or two chippers or pinchers of 2¹⁄₂ lb. weight. One large blocking-hammer of 30 or 32 lb., may very well serve for eight men. The value of a granite mason’s kit may be estimated, when in good working order, at about L.7. A very great revolution has taken place during a few years in the method of working granite. The most important change is the substitution of the hand-mall and chisel in the operation of putting the drafts or bands on the stones, in place of arris-picks, which made the workmanship clumsy, tedious and imperfect, by slowly grinding down the stone at a great expense of labour to the hewer, who was forced to remain bent forward in an irksome posture, without the relief which is obtained by occasionally shifting his position, a change, which, every one who has been long employed in any laborious occupation, knows well how to value. The introduction of the chipper may also be regarded as one of the most important modern improvements in the art of working granite; and had it not been for those changes, the actual expense of dressing the blocks for the Skerryvore Tower, as ascertained from the journals of the works, would have been exceeded by a sum of between L.4000 and L.5000; and it may even be questioned whether it would have been at all practicable with such tools to cut the dovetailed spaces of the floors out of the solid stone.

Excavation of Foundation for the Lighthouse Tower on the Skerryvore Rock. The excavation of the foundation of the Lighthouse Tower was the first operation which engaged my attention at Skerryvore Rock, at the beginning of the season of 1839. It was commenced on the 6th of May, and was continued up to the last hour of our remaining on the Rock, on the 3d of September. A more unpromising prospect of success in any work than that which presented itself at the commencement of our labours, I can scarcely conceive. The great irregularity of the surface, and the extraordinary hardness and unworkable nature of the material, together with the want of room on the Rock, greatly added to the other difficulties and delays, which could not fail, even under the most favourable circumstances, to attend the excavation of a foundation-pit on a rock at the distance of 12 miles from the land. The Rock, as already noticed, is a hard and tough gneiss, and required the expenditure of about four times as much labour and steel for boring as are generally consumed in boring the Aberdeenshire granite.

After a careful survey of the Rock, and having fully weighed all the risks of injuring the foundation, I determined at once to enter upon a horizontal cut, so as to lay bare a level floor of extent sufficient to contain the foundation pit for the Tower. The very rugged and uneven form of the Rock made this an almost necessary precaution, in order to prevent any misconception as to its real state, for it was traversed by numerous veins and bands inclined at various angles, on the position and extent of which the stability of the foundation in no small degree depended. That operation occupied 30 men for 102 days, and required the firing of no fewer than 246 shots, chiefly horizontal, while the quantity of material removed did not greatly exceed 2000 tons. It was a work of some hazard; for the small surface of the Rock confined us within 30, and sometimes within a dozen yards of the mines, while its form afforded us no cover from the flying splinters. The only precautions we could adopt were to cover the mines with mats and with coarse nets, which I had caused to be made during the previous winter, of the old ropes of one of the Lighthouse Tenders, and in each blast to apportion very carefully the charge of powder to the work that was to be done. That was managed with great skill by Charles Barclay, the foreman of the quarriers, who charged all the bores, and, along with myself, fired all the shots. So completely did the simple expedient of covering the bores with nets and mats check the flight of the stones, that, except on one or two occasions, none of the splinters reached us, and all the damage done was a slight injury to one of the cranes. Perhaps, also, our safety may, in some measure, be attributed to a change which I introduced into the mode of charging the horizontal shots, by which all the risk of pushing home the powder in the ordinary mode with the tamping rod is avoided. That change consisted in using a kind of shovel, formed of a rod, armed with a hollow half-cylinder of sheet copper, which contained the powder, and being inverted by giving the rod half a turn round its axis, made the powder drop out when the cylinder reached the bottom of the bore. It was, in all respects, excepting size, the same as the charging-rod used for great guns. The amount of materials removed by blasting, as nearly as I could ascertain, was only about 1000 cubic yards; and, taking all the circumstances into account, it may be doubted whether there be any instance in modern engineering of an operation of so small an extent occupying so much time, and involving so great risk. The blasting of the Rock, however, was not the only difficulty with which we had to contend, for it also became necessary to remove the quarried materials, amounting to about 2000 tons, into the deep water round us, to prevent their being thrown by the waves upon the Rock, and so endangering the future temporary Barrack. That was rather a laborious work, and occupied two cranes, with temporary runs and trucks, during the greater part of the time we spent on the Rock. I am well aware that the quantity of materials which I have just mentioned, will be apt to produce a smile from those who have been chiefly conversant with the gigantic but simple operations which generally characterize the great railways of this country; but if it be remembered that we were at the mercy of the winds and waves of the wide Atlantic, and were every day in the expectation of a sudden call to leave the Rock, and betake ourselves to the vessel, and on several occasions had our cranes and other tools swept into the sea, the slowness of our progress will excite less surprise; and still less will those who duly weigh the dangers of our daily life, both in our little vessel and on the Rock, and who, at the same time, reflect on the many striking proofs which we almost every hour experienced of the care of an Almighty hand, be disposed to withhold their sympathy from the heartfelt expressions of gratitude which often went round our little circle in the boats, as we rowed in the twilight from the Rock to the ship. Isolation from the world, in a situation of common danger, produces amongst most men a freer interchange of the feelings of dependence on the Almighty, than is common in the more chilly intercourse of ordinary life.

With a view to lessen the dangers of blasting in such a situation, I had provided a galvanic battery on the plan proposed by Mr Martyn Roberts, but I used it less frequently than I intended. The attachments of the wires were very liable to be broken from various causes, where there were many men congregated in a small space; and as we could not venture to leave the apparatus on the Rock, the frequent re-shipment of it in a heavy sea was another cause of the derangement of its parts. I soon, therefore, laid it aside, and only had recourse to it when any work was to be done under water, or in cases where the simultaneous firing of several mines (for which it is admirably adapted) was of importance in effecting any special purpose.

When the floor had been roughly levelled I again carefully surveyed the Rock, with the view of fixing precisely the site of the foundation-pit, and of taking advantage of its form and structure to adopt the largest diameter for the Tower of which the Rock would admit. In some places I found that parts of the Rock, apparently solid, had been undermined by the constant action of the waves, to the distance of 13 feet inward from its face; but none of those cavernous excavations reached the main nucleus, so that, after much deliberation and repeated examinations of all the veins and fissures, I was enabled to mark out a foundation-pit 42 feet in diameter, on one level throughout. That was a point of no small importance; and although it had cost great labour at the very outset, much time was saved by it in the subsequent stages of the work. Not only was the labour thereby avoided of cutting the rock into separate terraces, and fitting the blocks to each successive step, as was done by Smeaton at the Eddystone; but the certainty that we had a level foundation to start from, enabled us at once to commence the dressing of stones without regard to any irregularities in the surface of the Rock; and the building operations, when once commenced, continued unimpeded by the necessity for accommodating the courses to their places in the foundation-pit, so that the Tower soon rose above the level, at which there was the greatest risk of the stones being removed by the waves before the pressure of the superincumbent building had become great enough to retain them in their places.

The outline of the circular foundation pit, 42 feet in diameter, having been traced with a trainer on the rock, numerous jumper-holes were bored in various places, having their bottoms all terminating in one level plane, so as to serve as guides for the depth to which the basin was to be excavated. The depth did not exceed 15 inches below the average level, already laid bare by the cutting of the rough horizontal floor which has just been described; and before the close of the season of 1839, about one-third of the area of the circle had been cleared, and was ready for the final pick-dressing which prepared it for the reception of the first course. The excavation of this circular basin was conducted with the greatest caution, and few shots were permitted to be fired lest the foundation should in any place be shaken by the action of the gunpowder on any of the natural fissures of the Rock. The work was chiefly done by means of what are called plugs and feathers, the form of which has already been shewn in the woodcuts ([No. 12], p. 115). In that part of the work the bores were nearly horizontal, and the action of the plug and feathers was to throw up a thin superficial shelf or paring of rock of from 6 to 12 inches in depth, and not more than 2 feet square. By that painful process an area of about 1400 superficial feet was cleared. The chief trouble connected with that operation was cutting, by means of the pick, a vertical face for the entrance of the horizontal jumpers or boring rods; and wherever advantage could be taken of natural fissures it was gladly done. Another considerable source of labour was the dressing of the vertical edges of the basin, as that implied cutting a square check, 15 inches deep and about 130 feet long, in the hardest gneiss rock; and the labour attending which, can only be fully estimated by a practical stone-cutter who has wrought in such a material. The plan employed was to bore all around the periphery of the circle, 1⁵⁄₈ inch vertical jumper-holes, 6 inches apart, to the required depth, and to cut out the stone between them. The surface thus left was afterwards carefully dressed, so as to admit vertical and horizontal moulds, representing truly the form of the masonry which the check was intended to receive. The experience of the labour attending that operation gave me great reason for congratulation on having adopted a foundation on one level throughout, instead of cutting the rock into several terraces, at each of which the same labour of cutting angular checks must necessarily have been encountered. The cutting of the foundation occupied 20 men for 217 days in all, whereof 168 days were in the season of 1839, and the rest in the summer of 1840.

The minute details given in my account of the destruction of the first Barrack, have entirely superseded the need for any particular description of the fitting up of the second Barrack on the Rock; and I shall therefore confine myself to a brief notice of the work in the chronological order in which it occurred. Fitting up of the Second Barrack on the Rock. On the 1st of July, after the level floor for the foundation of the Tower had been roughly cleared, and all risk of injury from the firing of mines was past, the boring of holes for the fixtures of the second Barrack was begun; and so great were our exertions, that in the short period of fourteen days, the pyramidal frame-work on which the Barrack-house was to stand (see [Plate V.]), consisting of 13 beams, of about 50 feet in length, with all their braces, ties and stancheons, and the malleable iron cap which secured their union at the top, was firmly fixed on the Rock. After the pyramid was completed, the Barrack-house (which had previously been removed from North Bay, where, as already noticed, it had served as a temporary abode for the men who opened the quarries there), was transported, piece-meal, from Hynish to the Rock as required; for it was not considered prudent, after the experience of last year, to trust, even in the finest part of the season, a great quantity of timber to lashings on the Rock. The fitting-up of the Barrack-house was completed on the 3d September and occupied only eleven days; so that the whole work extended to only twenty-five days, a remarkably short time for such a work, in such a situation. That despatch, indeed, was only obtained by working (as we did both during the excavation of the foundation and the erection of the Barrack), at all times when the weather would permit, from four o’clock in the morning till eight, and even nine in the evening, with an interval of only half-an-hour for breakfast and the same for dinner. The erection of the Barrack was a work of great difficulty and anxiety; for, as every thing depended on the exact union of all its parts, the slightest error in any dimension would have stopped the work until it could be remedied, a delay which, in such a situation, would, at certain stages of its progress, have proved fatal to the whole structure. Sudden death of George Middlemiss. I cannot, therefore, omit this opportunity of paying a tribute, in passing, to the memory of the late Mr George Middlemiss, the foreman of the carpenters who fitted up the Barrack, whose zeal for the completion of the work was very conspicuous. Poor Middlemiss died very suddenly at Hynish, about a fortnight after the completion of his labours on the Rock. He had received some instructions from me, so late as 11 o’clock, on the night of the 20th September; and when one of the men went to call him next morning at 6 o’clock, he was found dead, and in such a state as led Mr Moxey, the surgeon attached to the works, after a careful examination, to conclude, that he had died of paralysis of the heart, about three hours before he was found, or not more than four hours after I had seen him, to all appearance, in perfect health!

Wharf and Landing-place on the Rock. No inconsiderable part of the labour of this season was devoted to the clearing of the landing-place, which was formed in a natural creek (see [Plate III.]) and in excavating the rocks in front of the line of wharf, so as to admit the vessels carrying the building materials to come alongside of it. That work could only be done at certain times of tide and during very fine weather, and was, therefore, tedious as well as hazardous. After two entire days spent in cutting with a sickle, mounted on a long pole, the thick cover of gigantic sea-weed, which hid the true form of the Rock from view, we were able to mark out the line of the wharf; and after all the mines were bored and charged and the tide had risen, and every one had retired from the spot, the whole were fired at the same instant, by means of the galvanic battery, to the great amazement and even terror of some of the native boatmen, who were obviously much puzzled to trace the mysterious links which connected the drawing of a string at the distance of about 100 yards, with a low murmur, like distant thunder, and a sudden commotion of the waters in the landing-place, which boiled up, and then belched forth a dense cloud of smoke; nor was their surprise lessened, when they saw that it had been followed by a large rent in the rock; for so effectually had the simultaneous firing of the mines done its work, that a flat face for a quay had been cleared in a moment, and little remained to be done, to give the appearance of a regular wharf and to fit it for the approach of a stone lighter, except attaching wooden fenders and a trap ladder.

Ring-bolts, Water-Tanks, and Railways. A good deal of time was also spent in fixing a great many ring-bolts on various parts of the Rock and its outlyers, for the use of the shipping, which we expected to carry stones to the Rock the next season and in clearing a line for a permanent iron railway, about 50 yards long, from the landing wharf to the Tower, the position of which is shewn in [Plate III.] The railway was used for the conveyance of materials from the stone-lighters to the building, and is now the highway for all the stores which pass from the wharf to the Tower. Means were also taken for laying down two cast-iron water-tanks on the Rock in tolerably sheltered positions, as shewn in [Plate III.] One of those tanks was completed and filled with water, but the sole-plate only of the other was fixed, as unfortunately one of the plates dropped from the vessel’s side into the water, while the seamen were lowering it into one of the boats, a loss which prevented the second tank from being finished till the next year. Those tanks, together, held about 900 gallons, and contained our chief supply of water during the whole subsequent progress of the works, when there were often about fifty men on the Rock.

Incidents of the Season. I shall conclude this Chapter, by noticing a few incidents which occurred during the season of 1839, serving, in some degree to throw light upon the peculiar difficulties we had to encounter, or tending to shew the importance of the work in which the Commissioners had engaged.

Effects of a gale from the S.W. On the 9th of August a strong gale suddenly sprang up from the S.W., which, while it lasted, caused us much alarm and anxiety at Hynish, whither we had been driven from our station at the Rock to seek shelter at the commencement of the storm. Several small pieces of timber, which we had left on the Rock when we were forced to leave it, came ashore in Balaphuil Bay; and it was generally reported in the Island that the Barrack had, for the second time, been destroyed. That report I did not credit, as I had great confidence in the fixtures which attached it to the Rock; but my anxiety to ascertain the true state of the case, led me to examine the south-eastern shore of Tyree, when all that could be discovered was a few pieces of loose timber, and one of the smith’s cooling tubs, which had been washed from the Rock. Next day, however, the smith’s bellows came ashore in the same Bay, and so little injured, that we had them repaired and put in use again on the Rock. On the 12th of August, when the weather permitted us to return to our station at the Skerryvore, we found all the timbers which had been lashed down with chains to the Rock scattered in every direction around the beams of the Barrack, the smith’s forge overturned, the bellows of course gone; one of the cranes also which had been used for the removal of the excavated materials had been swept away, and not a vestige of it left, except a small piece of one of the wooden stays, which the force of the waves had broken. But that which most of all surprised us, and gave us the greatest concern, as an alarming proof of the force of the sea and a source of great inconvenience and hazard during the rest of the season, was the disappearance of our moorings, which had been lost by the foundering of the cask buoy in the heavy surf which the gale had raised. During all the rest of our stay at the Rock that season, we were forced to ride at anchor in foul rocky ground of the worst and most irregular description, over which the vessel frequently drifted to a considerable distance, occasioning us no small fear for our safety. That was the second set of moorings which had disappeared at Skerryvore; and a stronger proof of the very great power of the western swell can hardly be imagined, as nothing of the kind had happened during the whole time the Bell Rock works were in progress. That circumstance also convinced us of the necessity of adopting vessels of small burden for landing the materials. So great, indeed, was the difficulty of hanging even the boats at the Rock, that on two occasions (on the nights of the 4th May and 12th July) we had both the boats half filled by the sea, and nine or ten men thrown out on the Rock by the kanting of one of the boats at the recoil of the wave. The landing department was indeed, throughout the whole season, attended with great difficulty, and was to me a source of constant anxiety; for, in the daily transport to and from the vessel and the Rock of 30 men, unaccustomed to boating, during a period of four months, it was more than could have been expected that we should have been preserved from the loss of either life or limb. On the night of the 3d September, when we left our anchorage at the Skerryvore for the season, every heart was full of rejoicing, and many cordial expressions of gratitude to our Almighty Protector were uttered in deep whispers by the more seriously disposed men, whose number bore a goodly proportion to our whole band. I cannot omit saying, in this place, that both Mr Macurich, who acted as landing-master on the Rock, and the late Mr Heddle, the master of the steam-tender, conducted the boating department in a most masterly style.

As an aggravation of our difficulties, we were occasionally much annoyed by the unprincipled and cowardly conduct of a few of the seamen, who, despite the contempt of their comrades, fearing or pretending to fear the risk of lying all night so near the face of the Rock, spared no pains to spread alarm, and made several attempts, Mutiny of the Crew. by threatening desertion, to extort a rise of wages. They even spoke of leaving the vessel at the Rock, which they could easily have done by some of the native boats which called in passing to see the progress of the works; and Mr Heddle, the master of the steamer, was forced to dismiss the mutineers on the first occasion when the vessel was driven for shelter to the land, and to rely during the rest of the season on the native boatmen to supply their place. That firm conduct had, for some time afterwards, the desired effect on those who remained; but the spirit of disaffection having spread pretty widely, we had subsequently several other instances of sudden desertion from the service.

In the course of my residence for four months on board the tender moored off the Rock, I had opportunities of witnessing many proofs of the great necessity which existed for a Light on the Skerryvore; and if I had ever entertained any doubt as to the beneficial effects of such an establishment, the experience of the season of 1839 must have entirely removed it. Near approach of Vessels to the Rock, and other circumstances shewing the importance of a Light on the Skerryvore. It often happened that for several days successively, not fewer than five or six vessels of large size, both outward and homeward bound, were visible at distances varying from 3 to 6 miles from the Rock; and much anxiety was often felt by us for the safety of those vessels, several of which approached so near the outlying rocks as to keep us for some time in the most painful suspense. On two occasions, more especially, I was about to direct the steam to be raised, in order that the Skerryvore tender might be sent to warn the masters of vessels of their danger, or if too late for that, to afford them assistance in case of accident. On the 29th of May a large schooner, and on the 13th of June a large brig ran right down upon the western outlyers, called Fresnel’s Rocks (which were covered at the time), and just put about in time to avoid striking; and on the 12th June, a fine foreign barque (apparently a Prussian) passed so close to Bo-Rhua as to leave us for a short time in doubt whether or not she had struck on it. On the 21st of June, also, a large brig came very near the rocks which lie off Tyree, at the base of Ben-Hynish, in trying to avoid Boinshley Rock, which lies about 5 miles to the N.W. of the Skerryvore. Those circumstances, together with the list of shipwrecks already given at page 23, afford strong proofs that the Skerryvore Rock occupies a most fatal position in a great fairway much frequented by large vessels bound to or from ports in the Irish Sea and in the Clyde.

There cannot be a doubt that many vessels have been wrecked on the Skerryvore and its numerous outlyers, being borne down upon the reef by the strong tide which runs at the rate of between four and five miles an hour at the height of spring tides; and the natives of Tyree have many stories about chains and anchors and hidden treasures, with which their fancy has filled every nook of the Rocks. To what extent those stories, which are often most circumstantially told, may be true, it is not easy to determine; but in the end of July 1839, we succeeded, under the guidance of a native boatman, in raising from a creek in one of the detached shelves to the south-west of the main Rock, an anchor worn by the action of the sea to a mere skeleton, a circumstance which so far corroborates the truth of their traditions.

CHAPTER VI.
OPERATIONS OF 1840.

In describing the progress of the works during the season of 1840, I shall speak of the various departments separately, as in the last chapter, beginning with the workyard at Hynish.

Hynish Workyard. During the preceding winter months, the establishment at Hynish was reduced to about fifty persons, of whom twenty-seven were masons employed chiefly in dressing blocks for the Lighthouse, in laying the stone platform in the workyard (on which each course was adjusted previously to its being shipped for the Rock, to prevent the occurrence of mistakes which might not be easily remedied there), and in building some additional barracks, masons’ sheds and a limekiln for the summer of 1840. The quarriers and labourers formed a party of about eighteen, and were engaged in cutting blocks in the Tyree quarries, which, although unfit for the Lighthouse Tower, were very suitable for the completion of the Pier at Hynish; while nine carpenters had full occupation in making moulds for dressing the Lighthouse blocks, preparing oaken treenails to be used in the lower courses of the Lighthouse Tower, and in dressing handles for the masons’ and quarriers’ tools. In the month of April, a reinforcement of thirty-seven masons from Aberdeen arrived at Hynish; and the greater number of them were at once employed in the dressing of stones for the Tower; while a few assisted in building the dressed materials in a temporary manner on the stone platform in the workyard already mentioned. The number of masons in the workyard, during the summer months, varied considerably, according to the state of the works on the Rock, where seldom fewer than thirty men were stationed throughout the whole working season. But the dressing of the stones for the Tower proceeded with considerable vigour; and notwithstanding the inroads necessarily made upon the men’s time, by their being frequently required to assist in the landing of materials from Mull, a work for which few of the Tyree men were fit, from their awkwardness in the management of cranes and all kinds of machinery or tackling, and also by the constant detachment of a considerable number both of men and of tools for the laborious work of dressing the foundation-pit at the Rock, upwards of 20,000 cubic feet of granite had been dressed and fitted on the platform, when I left Hynish in the end of October 1840.

Hynish Pier. During the whole of the summer, the traffic at the pier at Hynish was so great in landing materials from the Mull quarries, and in shipping stones for the Rock, that much inconvenience was felt from want of room. Nearly 4000 tons were shipped and discharged at the quay, independently altogether of the ballasting of each vessel which discharged at the pier, and the receiving, storing, and finally supplying coals to the steamer, which formed no inconsiderable item of the labour. Every exertion was made to extend the pier, so soon as the works at the Rock were closed for the season and the stone trade with Mull had ceased; and by great perseverance on the part of Mr James Scott, the foreman of the workyard, whom I always found ready, night and day, to second and even to anticipate my wishes in regard to the progress of the works, an additional length of 36 feet was added to the berthage of the quay before the winter had set in.

The Rock. The first landing on the Rock, for the purpose of resuming the work in 1840, was on the 30th April, when all things connected with the Barrack were found in nearly the same state in which we had left them seven months before. The red paint with which we had coated it had become nearly white, partly by a covering of sea-salt, and by blanching of the paint itself, but chiefly towards the top by the soil of the numerous sea-fowl which had perched on the roof. The timbers, also, bore the signs of being wave-washed, and in the more sheltered parts were tufted with the finer kinds of seaweed; the iron-work was much rusted and entirely divested of paint. The door had been firmly secured with lashings and bolts, and some difficulty was experienced in forcing an entrance into the interior, about the state of which, as our future abode, much curiosity was naturally felt by the men, who were desirous to know how it had weathered a seven months’ exposure to the waves of the Atlantic. It was with no small pleasure, therefore, that, when the door was opened and the windows unbarred and the sunshine admitted to dispel its gloom and chilly damp, we found, that although the water had forced its way through some of the imperfect seams in the window-frames, the interior shewed evident signs of the stability of the fabric, and was in some places so dry, that the greater part of the biscuits which we had left the year before, as a store for shipwrecked seamen who might find their way to the Rock, although some of them were wet and pulpy on the side nearest the outer walls, admitted of being dried, and when a little toasted at the fire, were palatable enough to hungry men, so that, in fact, we consumed the greater part of that stock before we entered on our new supply.

The most important change which had occurred during the winter, was the removal of a mass of rock in the neighbourhood of the foundation-pit, which had been shaken by the effects of the blasting operations of the previous year. That mass, the moving of which shewed that a great weight of water had passed over the Rock, weighed about five tons, and had been detached from its bed during a heavy gale from the N.W., in the month of March, and carried right across the foundation-pit to the Barrack, against one of the beams of which it had rested, and had partially injured the iron collars or glands by which the beam was secured. The stone was broken into small fragments by a party of men, who had been appointed to visit the Rock after heavy gales, and had landed on the 27th of March, to see the state of the Barrack. The men, in their anxiety to break down the block, which they feared might injure the Barrack, if thrown against it by the waves, and allured by the smoothness of the sea, most imprudently remained all night, mooring their boat in the landing creek, and trusting to the scanty stock of provisions which they had brought out, with the intention of at once returning to Hynish. The risk involved in such a proceeding, we afterwards had many opportunities of knowing during our stay on the Rock, as we were often forced to make fast all our materials, to prevent their being washed away by the sudden rising of the waves, especially about the time of high-water in spring-tides. The discomforts, however, experienced by the men on that occasion while in the Barrack, without fire, light or bedding, in a cold dark night of spring were such, that several of them did not afterwards much affect the Rock as a residence even in summer.

Owing to the great difficulty of landing on the Rock in the early part of May, few opportunities occurred of preparing the Barrack as a habitation; Life in the Barrack. and it was not until the 14th of that month that we were enabled to take up our quarters in it; and even then we were most uncomfortably lodged, as many of the smaller fittings which are essential to a wind-and-water-tight habitation had not been completed. During the first month we suffered much from the flooding of our apartments with water, at times when heavy sprays lashed the walls of the Barrack with great violence and also during rainy weather; and in northerly gales we had much difficulty in keeping ourselves warm. On one occasion, also, we were fourteen days without communication with the shore or the steamer; and during the greater part of that time we saw nothing but white fields of foam as far as the eye could reach, and heard nothing but the whistling of the wind and the thunder of the waves, which were at times so loud as to make it almost impossible to hear any one speak. For several days, the seas rose so high as to prevent our attempting to go down to the Rock; and the cold and comfortless nature of our abode reduced all hands to the necessity of seeking warmth in bed, where (rising only to our meals) we generally spent the greater part of the day listening to the howling of the winds and the beating of the waves, which occasionally made the house tremble in a startling manner. Such a scene, with the ruins of the former barrack not 20 yards from us, was calculated only to inspire the most desponding anticipations; and I well remember the undefined sense of dread that flashed across my mind, on being awakened one night by a heavy sea which struck the Barrack, and made my cot or hammock swing inwards from the wall, and was immediately followed by a cry of terror from the men in the apartment above me, most of whom, startled by the sound and tremour, immediately sprang from their berths to the floor, impressed with the idea that the whole fabric had been washed into the sea. The alarm, however, was very short and the solemn pause, which succeeded the cry, was soon followed by words of reassurance and congratulation. Towards the end of the fourteen days I began to grow very uneasy, as our provisions were drawing to a close; and when we were at length justified, by the state of the sea on the rock, in making the signal to those on shore (at the hour fixed for pointing the telescope at Hynish on the Barrack), that a landing could be effected, we had not more than twenty-four hours’ provision on the Rock, so that when the steamer came in sight she was hailed by all hands with the greatest joy!

The construction of the Barrack has already been very fully described, and a glance at [Plate V.] will be sufficient to give a pretty correct idea of the nature of our singular dwelling. Immediately under the wooden tower was an open gallery, the floor of which was removed at the end of each season, so as to allow free space for the passage of the sea during the storms of winter, but on which, during the summer, we kept the stock of coals, the tool-chests, the beef and beer casks, and other smaller materials which we could not, even at that season, safely leave on the Rock itself. Next came the kitchen and provision store, a six-sided apartment about 12 feet in diameter and somewhat more than 7 feet high, in which small space, curtailed as it was by the seven beams which passed through it, stood a caboose, capable of cooking for forty men, and various cupboards and lockers, lined with tin, for holding the biscuits, meal, flour, barley and other things needful for the sustenance of the human frame. That apartment, for protection against fire, was coated, partly with tin and partly with sheet-lead, which latter, although not in all respects the most desirable material to come in contact with that element, was found to be the only one which we could in some parts conveniently apply. The next storey was divided into two apartments, whereof one was shared by Mr Thomas Macurich, who superintended the landing of all the materials and Mr Charles Stewart, the foreman of the builders, and the other was allotted to myself. The apartments thus occupied consisted of a twelve-sided narrow space twisted around a centre pyramid, whose bevelled faces formed, as will in part be seen by inspecting [Plate V.], their sloping walls on one side. The half of that space constituted my apartment, which, I think, would be generally pronounced not over commodious; and when it is added that it contained my bed, desk, chair and table, and a stock of groceries, it will readily be imagined I had little room to spare for myself. So much attention was paid to economy of space, that the recesses of the pyramid formed by the meeting of the beams were boarded over and made into cupboards; while my cot, or framed hammock (which, during the night, rested upon brackets which could be folded close to the wall when not required), was, during the day, hoisted by pullies to the roof of the apartment, so as to leave me as much space to move about in as a prisoner could expect. The cornice of the apartment consisted of a narrow shelf adorned with books, which I found very needful helps to solitary life. The highest apartment was also twelve-sided, surmounted by a pyramidal roof and a small six-sided lantern or ventilator, and was lined round the sides with four tiers of berths, capable of accommodating thirty people. The closeness of that room was most intolerable, especially during the heat of fine weather in summer, at which time several of the men preferred taking a nap on the rock, with the clear blue sky for a canopy. The economy of our life on the Rock was strange enough. At half-past three in the morning we were called, and at four the work commenced, continuing till eight, when half-an-hour was given for breakfast: after which it was carried on till two, when another half-hour was given for dinner; and the work was again resumed and continued till seven, eight, and even nine o’clock, when anything urgent was in hand. Supper was then produced and eaten with more leisure and comfort in the cool of the evening. Such protracted exertion produced a continual drowsiness, and almost every one who sat down fell fast asleep. I have myself repeatedly fallen asleep in the middle of breakfast or dinner; and have not unfrequently awakened, pen in hand, with a half-written word on the paper! Yet life on the Skerryvore Rock was by no means destitute of its peculiar pleasures. The grandeur of the ocean’s rage, the deep murmur of the waves, the hoarse cry of the sea-birds, which wheeled continually over us, especially at our meals, the low moaning of the wind, or the gorgeous brightness of a glassy sea and a cloudless sky, and the solemn stillness of a deep blue vault, studded with stars, or cheered by the splendours of the full moon, were the phases of external things that often arrested our thoughts in a situation where, with all the bustle that sometimes prevailed, there was necessarily so much time for reflection. Those changes, together with the continual succession of hopes and fears connected with the important work in which we were engaged, and the oft-recurring calls for advice or direction, as well as occasional hours devoted to reading and correspondence, and the pleasures of news from home, were more than sufficient to reconcile me to, nay, to make me really enjoy, an uninterrupted residence, on one occasion, of not less than five weeks on that desert Rock.

During the first half of the season 30 men were engaged 14 hours a day in the preparation of Foundation-pit. the foundation-pit, which, as already said, was a work of the greatest labour. The Rock, indeed, was in many places so hard as often to make it seem hopeless that tools could make any impression on it. The time employed in the excavation and the number of tools expended on it, were very great, as a pick seldom stood more than three strokes in the harder quartzose veins; but our perseverance was at length amply rewarded by obtaining a foundation so level and so fairly wrought throughout the whole area of a circle 42 feet in diameter, as to present to the view the appearance of a gigantic basin of variegated marble; and so much pleased were the workmen themselves with the result of their protracted toil, that many of them expressed serious regret that the foundation must soon be covered up so, as (we trusted), never to be seen again. In the dressing of the Rock much inconvenience arose from the small splinters which flew out before the tools, sometimes rising to the height of 40 feet, and coming in at the windows of the Barrack; and after several injuries had been sustained, I at length found it necessary to send to Glasgow for fencing masks to protect the men’s faces. In all our work, nothing was more grudged than the occasional loss of half a day in baling out the water from the foundation-pit after it had been filled by a heavy sea.

Landing of materials on the Rock. Before we had made an actual trial of landing stones on a Rock at the distance of 12 miles from the nearest shore, exposed to the incessant beating of Atlantic waves, there was much room for doubt as to the measure of success to be expected; and, as the time approached, I naturally looked to the attempt with increasing anxiety, as to an experiment in a great measure decisive of the future complexion of our operations. Four small vessels, carrying from 16 to 19 tons, had been built at Leith and Dumbarton, for the purpose of carrying the stones on their decks, so as to admit of their being easily lifted by the crane, and so to avoid the risk which would have been incurred by any attempt to raise stones by a crane from the hold of a vessel moored to a rock in the open sea and moving about with every wave. Had that been attempted, the crane would, on many occasions, have been pulled down before the stone could be cleared from the hold. The vessels were very similar to those which were used for the same purpose at the Bell Rock; and I therefore beg leave to refer the reader to page 509, and to Plate XI. of my Father’s account of that work, for a description of them. Being decked all over, to give room for cargo (for they carried nothing in the hold but empty casks for the purpose of floating them in the event of their sustaining any injury), they were towed between Hynish and the Rock by the steamer, and being cast off as near the landing-place as possible, were taken by the boats to the creek, and moored with warps to the fenders at the quay.

The first trial of the lighters in landing stones on the Rock was made on the 20th of June, on which occasion both the steamer and the stone craft were decorated with flags; and due honour was done to the occasion of landing the first stone, by firing a salvo shot and drinking success to the works. The landing service throughout the whole progress of the works was one of much difficulty and anxiety and many narrow escapes were made; but it was managed with great prudence, and at the same time with unremitting energy, by Messrs Macurich and Heddle, in their several departments, both ashore and afloat. On many occasions the men who steered the lighters ran great risks; and it was often found necessary to lash them to the rails, to prevent their being thrown overboard by the sudden bounds of the vessels, or being carried away by the weight of water which swept their decks as they were towed through a heavy sea. Sometimes, also, we were forced, owing to the rush of the sea into the creek, which threatened to lift the vessels on the top of the Rock, to draw out the loaded lighters from the wharf without landing a single stone, after they had been towed through a stormy passage of 13 miles; and one day, during the very best part of the season, so sudden was the bounding of the vessel before the sea, that eight large warps were snapped like threads as the lighter was carried violently before a crested wave which rolled unexpectedly into the creek, while those who stood on her deck were thrown flat on their faces and imagined that the vessel had been laid high and dry on the top of the Rock. During the whole season, however, in the course of landing 800 tons of masonry on the Rock, too often in that dangerous manner, none of the dressed stones received any great damage, nor was any other injury of importance sustained.

The building of the Tower was commenced on the 4th July; Building the first stone. but it was not till the 7th that the ceremony of laying the foundation-stone was performed by His Grace the Duke of Argyll, who, as proprietor of the adjacent Island of Tyree, took a great interest in the success of the works, and on that day visited the Skerryvore with the Duchess of Argyll, the Marquis of Lorne, Lady Emma Campbell, and a party of friends, in the Toward Castle steamer. On that occasion His Grace expressed himself much pleased with the works and kindly left with me a donation of L.10 for the workmen.

The building operations in 1840 were entirely carried on by means of two cranes with moveable jibs, of which one was fixed just beyond the foundation, at the place shewn in [Plate III.], between the landing quay and the Tower, and was chiefly used in bringing forward the materials; and the other, placed in the centre of the Tower, served for laying the stones, and was raised along with the rise of the building. So perfectly had the stones been dressed in the workyard at Tyree, that no alteration or paring of the beds or joints was required; and such was the facility afforded by the building apparatus, that by working 14 hours, we occasionally set, through the activity of Mr Charles Stewart, the foreman builder, so many as 85 blocks in a day. The first course of masonry was laid by means of a wooden trainer; but the place of all the subsequent stones was, as already noticed, regulated by the use of plumb-templets, whose inner faces were arcs of the generating hyperbola. By those means we succeeded in setting, in a most perfect manner, six courses, which carried the building to the height of 8 feet 2 inches, and contained a mass equal to 10,780 cubic feet. That quantity is not greatly less than the whole materials of the Eddystone Lighthouse Tower, which, according to my computations from the drawings of Smeaton, do not exceed 13,300 cubic feet, and is somewhat more than one-third of the contents of the Bell Rock Tower, which are about 28,500 cubic feet. That frustum was also nearly equal to one-fifth part of the whole mass of the proposed building, which is about 56,000 cubic feet. Of the six courses, the first three are of Hynish gneiss, and the rest are of granite from the Ross of Mull. The comparative merits of those two materials may be stated as follows:—The Hynish stone is harder, and susceptible of finer workmanship, and perhaps its most perfect blocks are more durable; but it requires much more labour in dressing than the Mull granite, which is more homogeneous in its structure and is not intersected by hard veins, like those which occur in the gneiss of Tyree. There is good reason also for concluding that the Mull stone is sufficiently durable, because it contains but a small proportion of micaceous matter, and in its texture closely resembles some of the blocks of St Oran’s chapel in the neighbouring Island of Iona, which have resisted the action of the weather, it is believed, for more than 600 years and still retain the marks left by the tools of the workmen. I had also carefully compared the density of the Hynish and Mull stones, by weighing blocks of known dimensions, and found that it requires 13·16 cubic feet of the former, and 13·66 cubic feet of the latter to weigh one ton, a difference much less than the appearance of the stone would lead one to expect. A Tower of the dimensions of that at Skerryvore, built entirely of Hynish stone, would have weighed about 4308 tons, while the same mass of Mull stone would weigh 4252 tons, leaving a difference of not more than 156 tons in favour of the Hynish stone.

The mortar employed in the building was composed of equal parts of Aberdda lime and Pozzolano earth, and was therefore identical, in its composition, with that used by Smeaton at the Eddystone. Not having been able, after searching the neighbouring islands, to obtain good sand, I found it inexpedient to adopt the proportion of equal parts of lime, sand, and Pozzolano, which were so successfully used at the Bell Rock; but so perfect was the adhesion of the mortar used at the Skerryvore, that in that mass of 800 tons only two small leaks were discernible, which being ripped or opened with an iron, and allowed to run dry, were afterwards carefully repointed, and have never since shewn the slightest symptoms of leaking.

CHAPTER VII.
OPERATIONS OF 1841.

Hynish workyard. The workyard at Hynish presented a very busy scene during the summer and winter of 1840; and the desolation and misery of the surrounding hamlets of Tyree seemed to enhance the satisfaction of looking on our small colony, where about 150 souls were collected in a neat quadrangle of cleanly houses, conspicuous by their chimnies and windows amongst the hovels of the poor Hebrideans, who generally make no outlet for the smoke in their gloomy dwellings, but permit it to escape by the doors. The regular meals and comfortable lodgings and the cleanly and energetic habits of the Lowland workmen, whose days were spent in toil and their evenings, most generally, in the sober recreations of reading and singing, formed a cheering contrast to the listless, dispirited, and squalid look of the poor Celts, who have none of the comforts of civilized life and are equally ignorant of the value of time and the pleasures of activity.

The number of masons employed in 1841, varied from 60 to 84 and they were chiefly engaged in dressing blocks for the Lighthouse-Tower, in discharging the cargoes of vessels loaded with stone from Mull and also in shipping stones for the Rock, in which operation, their acquaintance with the handling of dressed materials and their readiness in working the cranes, made them very useful in directing and also in working along with the native labourers, who, partly from incapacity and partly from excessive indolence, could not be trusted for a moment to themselves. During that year, upwards of 38,000 cubic feet of granite were dressed into blocks with straight beds and joints, and with faces of double curvature, so as to suit the contour of the Tower, when arranged in the wall. The blocks were also fitted with stone joggles, for retaining them in their places, and with lewis-holes for raising them in the manner usually practised in building materials of that description. Of those materials upwards of 70 blocks were floor-stones (see Plans of 84th and 85th courses, [Plate VIII.]), dovetailed on the heads, checked on the joints and having a plain surface on the upper and a concave one on the under bed. The necessity of preserving throughout their entire joints a perfect uniformity of bearing, made the dressing of those materials a work of great nicety; and each stone, as before noticed, being cut according to moulds, was fitted temporarily in its place on the platform at Hynish, previously to its being laid aside as ready for transport to the Rock. Those various operations were conducted with great care; and the stones, which were regularly arranged and numbered according to a schedule, formed, at the time I left the workyard in the end of October, a considerable pile, bearing ample testimony to the diligence and zeal of Mr James Scott, the foreman of the workyard and leader of the party ashore.

Owing to the uncertain and stormy weather in spring, it was not till the 13th of May, that the first landing was effected on the Rock. The Rock. The result of our visit, however, was most satisfactory. We found the Barrack quite as we had last seen it six months before; and not one joint of the pile of masonry, which we had left exposed to the waves, had been shaken or started. The Railway and Landing Wharf, although much exposed to the breach of the sea, had survived the winter’s storms with no greater damage than the loss of one of the sleepers or beams, on which the rails rested, which had been torn by the waves from its fixtures to the rock. It was not till a week after our first landing that we were enabled again to take up our quarters on the Rock; for we had few landings in the mean time, and some of them, owing to the heavy surf which played round the Rock, were of no very satisfactory kind. Our first experience of this season was indeed far from inviting. So difficult was the first landing, that we were forced to direct all our endeavours to laying in a small stock of provisions in the Barrack, before being left on the Rock; and, considering the scanty nature of the supplies which the weather permitted us to secure, it was thought prudent to restrict the number of men to eight masons and myself, with as many tools as we could land, to enable them to make the necessary repairs and arrangements before fairly commencing for the season the works of a more strictly progressive character. The vessel then returned to Tyree with the rest of the men and all the heavy apparatus which we could not land; and, to add to the unpleasantness of being left in such a position, with the improbability of a visit from the vessel for several days, one of the masons took alarmingly ill soon after the steamer was too far off for a signal, and suffered so acutely during the whole night, that his piercing cries in the spasms which accompanied his disorder, combined with the howling of a strong north-wester and the incessant lash of the waves, deprived the whole party of sleep during the first night. In this uncomfortable predicament, until the steamer returned on the 22d, we spent two days exposed to winds piercingly cold and in apartments soaked with spray, which found its way through inlets which had been made by the winter’s storms. We were not sorry, at the same time, to have an opportunity of removing the poor man to the care of Dr Campbell, the surgeon who was attached to the workyard at Hynish and of reinforcing our stock of provisions and the detachment of men. We also succeeded in landing the cranes and other building apparatus, which, owing to the heavy surf on the 20th, we had not been able to accomplish.

The few first days after getting fairly established in our habitation for the season, were occupied in extending the railway to a point on the northern part of the Rock, somewhat sheltered during certain seas (see [Plate III.]), where a crane for stowing the materials previously to building them had been erected; and thus it was not till the 25th of May that the first cargo of stones was landed. Next day a crane (then thirty-four years old), which had been used in the building of the Bell Rock Lighthouse, was placed on the top of the masonry, and the more cheering operations of mixing the mortar and of setting stones were begun.

In spite of the unfavourable state of the weather and the continual distraction of our exertions, occasioned by storms and the landing of materials, we continued our operations with such vigour as to complete the solid part of the masonry of the Tower on the 8th July. Until the building had reached to the level of 15 feet, the work was carried on by the use of two jib-cranes, one on the Rock and the other on the Tower, by means of which latter the stones were set, after being brought to hand by the first. But above that level, shear-legs similar to those used at the Eddystone, were employed. Those shear-legs were about 50 feet high, and were erected in the situation, at the side of the Tower, shewn in [Plate III.] They consisted of two spars attached at the base to jointed sockets batted into the Rock, and connected at the top by means of a crosshead of timber. The jointed sockets permitted the shears to hang forward at any angle suited to the level and distance of the part of the Tower to be reached; and chain guys both in front and behind, secured them from falling either backwards or forwards. At the crosshead hung an iron sheave with a chain, one end of which was provided with a hook for raising stones, while the other was wound around the barrel of a crab machine well batted down to the rock, by working which the blocks were raised to such a level as to be within reach of the building crane on the top of the masonry. The shear-poles were used, until the building of the Tower was completed, to raise the stones the first lift of forty feet above the Rock. In the later stages of the work, the stones, instead of being taken by the building cranes directly from the shear-poles, were raised from storey to storey by means of crabs placed inside the Tower, which worked chains, reeved through sheaves hanging from the end of beams projecting from the windows. Such beams are called needles, and are described at page 504, and shewn in Plate IX., fig. 3, of my Father’s Account of the Bell Rock Lighthouse, where they were used for the same purpose.

During the early part of the season the weather was intensely cold, with showers of sleet and heavier showers of spray, which dashed round us in all directions, to the great discomfort of the poor masons, whose apartments did not admit of a large wardrobe, while they had not the benefit of much room for drying their clothes at the small coboose or cooking-stove in the Barrack. For days together, also, the men were left without building materials, owing to the impossibility of landing them, or, what was worse, without the power of building what we had on hand in consequence of the violence of the winds. During such times we often felt much anxiety about the safety of the stones which we had piled on the rock ready for being built; and it took no small trouble, by the occasional application of the crane, to save them from being swept into the sea by the surf. The Waves. Nothing struck me more than the illusive effect produced on the mind by the great waves which rolled past the rock. The rapidity of their movements, and the noise which accompanied their passage through the gullies and rents of the rugged reef, seemed to give them the appearance of being much larger than they really were; and, even when viewed from the Tower, after it had risen to the height of 30 feet, they seemed, on approaching the rock, to be on the eve of washing right over the top of the building and sweeping all before them into the sea. It was a long time before, by continually watching the waves and comparing their apparent height with the results of their impact on the rock, we were enabled to correct our notions of their magnitude, so as to mark the approach of their crested curling heads with composure; and some of the party never became sufficiently familiarized with those visitors, to avoid suddenly looking round when the rush of a breaker was heard behind them, or recoiling a few paces when they saw its towering crest apparently about to burst in a torrent over their heads. It was only after a long residence on the rock and continual experimental observation, that I acquired confidence to approach within a few feet of the point which I expected the breakers to reach. I occasionally suffered for my temerity, by being thoroughly drenched with spray; but by long perseverance, I attained considerable skill in predicting the limits of their influence, though ever and anon an extraordinary wave overthrew all our confidence, by bursting far above the boundaries which we had assigned in our minds. That, however, did not generally occur in calm weather, but after strong gales from the N.W., when the waves had assumed the larger and more flattened form known by the name of the ground-swell. To gauge the height of those waves by means of a vertical rod, graduated with large divisions, so as to be read at a little distance, as the waves washed it in passing, was an object I had long in view; but I found it utterly impossible to apply any fixture in the deep water, in a situation fitted for the purpose. By making numerous comparisons, however, of the waves, with various known points of rock near the main Rock, and by availing myself of the observations of some of the more intelligent of the masons, I was led to conclude, that the greatest elevation of an unbroken wave, measuring from the hollow to the crest, does not, in the sea around the Skerryvore, exceed 15 feet; but the sailors, perhaps from their being less accustomed to accurate measurement, generally estimated it at 30 or even 40 feet. Colours of breaking Waves. I was often much interested, while I sat watching the waves that boiled round us on every side, to observe the peculiar tints which they assumed at the moment of breaking, passing as they did from the bluish-green colour of solid water by very rapid changes, to a delicate and very evanescent blush of rose colour, which invariably accompanied their greatest state of comminution or disintegration. Those appearances I have often observed in other places, and I supposed them to be produced by reflection from the thin plates of water; and took them for indications of the perfect homogeneousness of the sea-water, in regard to density, and also of the similarity of its condition at the moment of breaking.

The Seals. Amongst the many wonders of the “great deep,” which we witnessed at the Skerryvore, not the least is the agility and power displayed by the unshapely seal. I have often seen half a dozen of those animals round the Rock, playing on the surface or riding on the crests of curling waves, come so close as to permit us to see their eyes and head, and lead us to expect that they would be thrown high and dry at the foot of the Tower; when suddenly they performed a somersault within a few feet of the Rock, and diving into the flaky and wreathing foam, disappeared and as suddenly reappeared a hundred yards off, uttering a strange low cry, as we supposed, of satisfaction at having caught a fish. At such times the surf often drove among the crevices of the Rock a bleeding cod, from whose back a seal had taken a single moderate bite, leaving the rest to some less fastidious fisher.

The latter part of the season, although not so stormy as the first, was far from being favourable for the building operations which, on one occasion, even during the month of July, were suspended for five days by a violent gale, which made it unsafe to attempt standing on the Tower. Happily the wind was from the N.E., a quarter from which it has comparatively little power in raising heavy seas, otherwise we should infallibly have lost a large part of the dressed materials which lay piled on the Rock, and, in all probability, should have had our work thus prematurely cut short in the middle of summer.

After building a few courses above the level of the solid part of the Tower, the jib-crane could no longer be conveniently used, and recourse was had to a balance-crane, which, during the previous winter, I had caused to be constructed at Edinburgh, in the workshop of Mr James Dove. That apparatus, which, except as to its greater size and strength, in order to suit the greater dimensions of the Tower, was almost identical with that which was used at the Bell Rock, is shewn in [Plate IX.]; and it is only necessary, in this place, to notice its general construction and mode of working, which is also shewn in Plate XVII. of my Father’s Account of the Bell Rock Lighthouse. In the hollow of the Tower, a cast-iron pipe or pillar was erected, susceptible of being lengthened as the Tower rose, by means of additional pieces of pillar let in by spigot and faucet joints; and on the pillar a frame of iron was placed capable of revolving freely round it, and carrying two trussed arms and a double train of barrels and gearing. On the one arm hung a cylindric weight of cast-iron, which could be moved along it by means of the gearing, so as to increase or diminish by leverage its effect as a counterpoise; and on the other was a roller. The roller was so connected with the weight on the opposite arm, as to move along with it, receding from, or approaching to, the centre pillar of iron in the same manner as the weight did. From the roller hung a sheave, over which a chain moved, with a hook at the end for raising the stones. When a stone was to be raised, the weight and the sheave were drawn out to the end of the arms of the crane, which projected over the outside of the walls of the Tower, and they were held in their places by simply locking the gearing which moved them. The second train of gearing was then brought into play to work the chain which hung over the sheave, and so to raise the stone to a height sufficient to clear the top of the wall. When in that position, the first train of gearing was slowly unlocked and the slight declivity inwards from the end of the arms formed an inclined plane, along which the roller carrying the sheave was allowed slowly to move (one man using a break on the gearing to prevent a rapid run), while the first train of gearing was slowly wound by the others, so as to take up the chain which passed over the sheave, and thus to keep the stone from descending too low in proportion as it approached the centre of the Tower. When the stone so raised had reached such a position as to hang right over the wall, the crane was made to turn round the centre column in any direction that was necessary, in order to bring it exactly above the place where it was to be set; and by working either train of gearing, it could be moved horizontally or vertically in any way that was required. The men who wrought the crane, stood on two small stages of planks attached to either side of the framework, and moving round the shaft along with it.

The balance-crane was safely landed on the Rock on the 20th July and on the 25th it was erected in working order on the top of the masonry. On the afternoon of that day, I had the satisfaction of seeing it put to a severe trial in raising a stone of nearly two tons weight and drawing it from the shear-poles already noticed to the top of the building. As that trial was made at an earlier stage of the works than was originally intended, the Tower was of larger diameter than was quite suited to the arrangements of the crane, which was consequently subjected to the weight of the stone at the very point of the jib. I felt no small anxiety as to the result, and had taken the precaution to relieve the centre pillar or shaft, on which the crane swung, from part of its burden, by means of a guy attached to a lewis-bat on the top of the building; yet even with that aid, the point of the jib was depressed 6 or 8 inches on a length of 14 feet. That test, however, having been successfully passed and not the slightest trace of any injury having been discoverable in any part of the crane, we continued to work it with perfect confidence and in the most satisfactory manner throughout the whole season until the close of the Rock operations for the year on the 17th of August.

The mass of masonry built during the season was 30,300 cubic feet, a quantity considerably more than double that contained in the Eddystone and somewhat more than the mass of the Bell Rock. The whole was very carefully set and when gauged at the upper bed of each course was found to preserve the diameter due to the height, according to the calculated dimensions, within a fraction rarely exceeding ¹⁄₁₆th of an inch. The height of the mass also, when measured, exceeded the specified height only by half an inch. The mortar employed was composed of equal parts of lime from the Halkin Mountain in North Wales and Pozzolano; and I consider it if possible superior to that produced from the lime of Aberdda. When we left the Rock this season, two apartments were covered in and the third was nearly completed, as will appear from the section ([Plate III.]) (on which the progress of the several seasons is marked), and only about one-third of the whole Tower remained to be built.

Our last work on the Rock before leaving it for the season on the 17th August, was to cover the balance-crane with a strong tarpaulin in order to protect it as much as possible from the weather and also to make a temporary lightning-conductor from the top of the building to the sea.

The extent of work done during the season of 1841 at the Rock, must in a great measure be attributed to the advantage of steam attendance, without which numerous favourable opportunities of landing materials must necessarily have been lost, from the uncertainty which pervades all the movements of sailing craft. The number of lighters towed out and discharged at the Rock was 120; and it is remarkable that no accident of importance occurred, although many risks were run, from the breaking of warps while the craft lay moored to the landing quay during heavy seas. I cannot omit in this place to record my sense of the services rendered to the works by the late Mr James Heddle, who commanded the steamer and who died from some consumptive disease soon after the close of the season’s operations. Mr Heddle’s health had been somewhat enfeebled towards the latter part of the autumn; and his excessive exertions and continued exposure during his arduous service, in some measure, I fear, hastened the crisis of his disease, which at length terminated suddenly by the rupture of an abscess in the lungs. Of his anxiety to forward the work, and his unwearied exertion in the discharge of his harassing duty at Skerryvore, which frequently allowed him less than twenty hours sleep in a week, I cannot speak too highly, as I consider his intrepidity and zeal to have been one of the most efficient causes of our success ever since the commencement of the works on the Rock in 1839. Mr Heddle possessed attainments superior to those generally found among persons in his walk of life and was in every respect a most estimable man.

CHAPTER VIII.
OPERATIONS OF 1842.

On the 17th of April 1842, I made my first landing on the Skerryvore, for the season, State of the Rock in Spring of 1842. and found traces of very heavy seas having passed over the Rock during the preceding winter. Its surface was washed quite clean from all the scattered materials which were left lying on it at the end of the last season; and the building, to the height of 6 or 8 feet from the foundation, was covered with a thick coating of green sea-weed. The railway had suffered considerably from large stones having been thrown upon it; and several blocks of about half a ton in weight were found wedged into the deep fissures of the Rock, and lying among the main timbers of the Barrack. Heavy sprays had been playing over the Tower, in the upper uncovered apartment of which a great number of water-worn pebbles or boulders were found. Those stones had been raised by the heavy surf and deposited on the floor of the apartment and on the top of the wall at a height of no less than 60 feet above high watermark; but the balance-crane, which had stood all winter on the top of the Tower, had sustained no damage, although the canvass cover was torn to shreds by the action of the weather. In the Barrack every thing was in good order except the smoke-funnel, which, from the effects of the sea-water, was riddled full of holes and required to be completely renewed.

As I had resolved to keep, during the summer of 1842, a complement of about eighteen or twenty seamen on the Rock, in addition to the usual detachment of masons, in order to work the crabs for raising the materials to the top of the Tower by successive stages; Commencement of Rock operations. my first step was to set about preparing additional accommodation in the Barrack, by converting the open gallery (called store for coals, &c., in [Plate V.]), immediately below the cook-house, into a covered apartment for lodgings for the additional hands. I accordingly landed on the 20th of April, with a stock of provisions, water and fuel and a party of joiners and a smith, to prepare that apartment by simply flooring over the joists of the gallery and closing the triangular, or rather trapezoïdal, spaces between the uprights of the Barrack, with double planking, protected on the seams with painted canvass, so as to render them impervious to the heavy sprays which, even in summer, dashed forcibly on the lower parts of the Barrack. Windows were formed on the sides least exposed to the intrusion of the sea; but, with all our precautions, we could not succeed in keeping dry even the cots or hammocks, which were suspended there; and it must be admitted that the addition to the Barrack proved, in bad weather, but a comfortless retreat, the inconveniences of which few but seamen would have patiently endured. Those discomforts, however, were to a certain extent, counterbalanced by some advantages which that singular abode possessed in hot weather; for, at such times, its inhabitants enjoyed more room, freer air, and more tolerable temperature, than any of their neighbours in the highest storey could obtain, owing to the greater number of persons in that part of the Barrack and its exposure to the heat of the cook’s stove.

During the remainder of the month of April and the commencement of May we had frequent stiff gales; and it often happened that the men could not venture out of the Barrack, owing to the heavy sea which swept over the Rock. The crane, too, which had been erected at the wharf for unloading the stones, although its top stood about 8 feet above the Rock, was often buried in the breakers and seemed in hourly danger of being carried away, an event which we were the more ready to fear from our experience in a former season, when the crane disappeared during a heavy westerly gale. The sea on those occasions also broke so heavily on the Barrack, that the windows of my apartment, which were about 55 feet above the sea, were often darkened by the sheet of water which flowed over them after the house had been struck by a wave. From those causes it was not till the 18th May that we were enabled to occupy the Rock in full force; and on the day following we commenced building the 38th course on the top of the last year’s work.

After that period we had a long continuance of north-easterly winds, which always brought both smooth water for landing materials and dry weather for building; so that by the 23d of May our work had made such progress and the Tower had risen so high, that the chain of the balance-crane, which had been raised along with the building, by sliding it upwards on the cast-iron pillar or shaft placed in the centre of the Tower, could not reach the top of the shear-poles, by which the stones were raised to the level of about 40 feet above the Rock; and it was found necessary to rig from the lowest window a beam or needle (in the manner described at [page 155], and as also shewn in Plate IX. of my Father’s Account of the Bell-Rock Lighthouse), as an intermediate stage between the top of the Tower and the shear-poles on the Rock. The needle, as already noticed, projected horizontally from the window and the stones were raised by a chain which passed over the sheave at its outer end and was wrought by means of a crab placed in the interior of the Tower. In that manner we continued for about six weeks, with little interruption from the weather, to raise the blocks of stone to the top of the Tower by successive needles from storey to storey; while the mortar, lewis-bats and other lighter materials were raised at once by means of a line wrought by a windlass placed on the Rock.

On the night of Saturday the 9th of July, however, a heavy sea, caused by a combination of high tides and strong gales, threw down some of the stones of the belt course which lay piled up round the base of the Tower ready to be raised for building; and they were with great difficulty, but most happily, saved from the insatiable deep. The loss of any of the stones of that course would have been a serious obstacle to the progress of the works and might have prevented our completing the erection of the lantern until next year; and indeed, as that course formed a prominent feature of the Tower, any slight injury even to the arris or corners of the outer face would have been much to be regretted. It was with great satisfaction, therefore, that it was found on examination next morning that none of the stones had sustained the slightest damage.

Last Stone. On the 21st July the last stones of the Tower were safely landed on the Rock, under a salute from the steamer, as an expression, no doubt, of the satisfaction which the commander Mr Kerr and his crew naturally felt at having successfully brought out not fewer than 75 lighter loads, or about 1500 tons, of stone during the season, as well as in some measure of their joy at the prospect of a speedy and happy termination of our arduous labours. The process of landing, indeed, owing to the fine weather that prevailed throughout the season, was very easy, compared with that of former years; in proof of which, I may state, that in 1841, there were often as many as five warps broken at a single landing, while in 1842, not a single rope was broken in the discharging of the stones. On the 25th July the last stone of the parapet or top-course was built; and immediately thereafter we proceeded to remove from the Tower, the balance-crane and the cast-iron pillar on which it was swung, and to make way for the erection of the Lantern.

In looking back upon the works we found great cause for thankfulness for the successful conclusion of the building operations, without loss of life, or even the occurrence of any serious accident, excepting the destruction of the first Barrack in November 1839. It also gave me great satisfaction to reflect that, however difficult a rigid adherence to scrupulous accuracy of workmanship may be in such a situation as the Skerryvore, it had nevertheless, from the exactness with which the stones were dressed, on no occasion been necessary, throughout the execution of the whole work, to deviate from the rule which I had laid down of carefully gauging the diameter of each course and of admitting no variation from the true form materially exceeding ¹⁄₈ inch. Every part of the stone work, indeed, was fitted in an accurate manner and the floor stones, in particular, which serve as ties across the building, were finely dressed and carefully set. All opportunities were also embraced, whenever it was practicable, to grout each course over night that the recent masonry might be in a state fit for building upon in the morning; and by those precautions and the peculiar properties of the mortar used, any disadvantages from very rapid building were entirely avoided. Even the elliptic cavetto which forms the cornice and which projects no less than three feet from the face of the wall, although bearing a very heavy entablature or plinth, never gave any signs of settling outwards; and when I examined it from a stage hung from the end of the balance-crane just before it was removed, there was no appearance of any change in the thickness of the joints, although the outer heads of the stones had been purposely kept a little high to allow for any tendency to settlement. The effect of the cornice is very bold and striking and is quite in accordance with the simple and almost severe style of the pillar itself. The masonry of the Tower is 137 feet 11 inches in height and it contains 58,580 cubic feet or about 4308 tons.

The day after landing the last stone of the parapet, the steamer started from Tyree for Greenock, with two lighters in tow, for the transport of The Lantern. the Lantern; and by the 10th of August the whole was landed on the Rock. No time was lost in preparing the beds for the sole-plates of the Lantern, and that operation had been nearly completed when my Father, in the course of his annual tour of inspection, as Engineer for the Northern Lights, visited the Rock, two days after the iron work had been landed. By the 16th the whole of the sashes and the frame of the roof were to their places; and on the same day the fixtures of the lightning-conductor were completed. On the 18th of August Mr Bruce, the Sheriff of Argyll, and some gentlemen who accompanied him and had spent the preceding night at Hynish, visited the Rock; and, after breakfasting at the base of the Tower, ascended to the top and minutely inspected every part of the work. They afterwards returned to Hynish, whither I accompanied them and had an opportunity of pointing out to Mr Bruce the various works in progress there. The party sailed for Oban in the afternoon of the same day.

From want of room on the Rock it was found necessary to build the roof of the Lantern in separate pieces instead of rivetting together the sheets of which it was composed on the ground, and raising the whole to the top in one mass, as is usually done; but, in spite of that disadvantage, the work was brought to a close for the season on the 14th September, on which day the glazing of the Lantern was completed and the glass was covered with a framework of timber to protect it from the sea-fowls which frequent in myriads the Rock and the Tower. The workmen were, on the same day, removed from the Rock, although with much difficulty, owing to the heavy surf which broke over the landing-place and rendered the embarkation more perilous than almost any I had before experienced at the Skerryvore.

CHAPTER IX.
CONCLUDING OPERATIONS AND EXHIBITION OF THE LIGHT.

The shores of Tyree, as already often noticed in these pages, and as deplored by Martin 140 years ago, in his Account of the Hebrides, afford few places of safety fit even for boats. It had therefore been determined, by the Commissioners, that any attempt at Harbour Works. the construction of a harbour should be strictly confined to the provision of a place of shelter for the vessel which was to attend the Lighthouse. Much attention had been bestowed on the subject, not merely by myself during my five years’ acquaintance with Tyree, but also by Mr Thomas Stevenson, who succeeded me in the charge of the works at Hynish, at the time when I was appointed Engineer to the Lighthouse Board in January 1843, after the completion of the masonry of the Tower. A small sandy beach at Hynish, which lies embayed between rugged rocks, had been selected as the fittest place for the pier; and all the materials had been landed and shipped there, so that we naturally looked to it as the site for the projected harbour, not only as presenting works already finished, which might be made available as part of a more extended plan, but as a place which, during an experience of some years, had justified our anticipations as to its being less frequently disturbed during stormy weather than most of the neighbouring creeks. All that was contemplated in the proposed plan, was to form a small basin in which the vessel could lie sheltered in all states of the weather, and from which she could find an easy departure in any condition of the sea which would permit a landing to be made on the Rock. The Skerryvore Steamer having been sold and a small vessel of 35 tons, named the “Francis,” having been purchased at Deal, the dock accommodation at Hynish was, for the sake of economy, laid out with reference to the shelter of that vessel. It was calculated that a basin 100 feet in length and 50 feet wide, would afford sufficient room for such a vessel; and as her draught of water is between 7 and 8 feet, it was thought sufficient to provide for a depth of about 12 feet at high water of spring-tides, which, it was expected, would render the dock accessible during good springs at about three quarters flood.

The exposure of the shore at Hynish, to the effects of heavy westerly swells, made it desirable to avoid carrying the entrance of the basin so far seaward, as, under more favourable circumstances, would undoubtedly have been done; and it was accordingly determined that the landing pier should be extended to about 40 feet seaward of low-water mark, and terminated in a round head, as shewn in [Plate X.], having a talus wall on its seaward face, composed of rough blocks, arranged in courses regularly receding, so as to form a slope of 45° of inclination, as shewn in [Plate XI.] The inner face of that pier, being nearly vertical and guarded by fenders of timber, had served as the quay for landing and shipping stones and other stores and it now forms one side of the basin or dock. The other side consists of a shorter talus wall, built about 60 feet to the westward of the first, and, together with the crossheads projecting from each wall and containing the gateway, completes the inclosure of the basin. In the gateway, booms are employed, as the shifting nature of the sand and the heavy seas render gates inadmissible. The space contained between those walls was left completely dry at low water of spring-tides, and was chiefly composed of rock, covered with a thin layer of shifting sand, which varied in depth with the state of the wind and sea. The rocky matter, consisting of decomposed gneiss, was excavated to the extent of about 5000 tons, in three separate compartments, protected by successive dams of rubble masonry, built with Pozzolano mortar, and presenting an aggregate area of 7339 square feet. Those dams, two feet thick, proved so water-tight, that by the aid of a small hand-pump, the excavation and the building of the entrance heads of the booms went regularly forward without any delay, although the men worked in the bottom of the pit, surrounded on all sides by the sea, which, at high water of spring-tides, rose 17 feet above them. The dams were sheltered from the action of the swell by a temporary breakwater of heavy blocks, which formed a convenient roadway for the transport of the materials during the progress of the works, and which were removed at the close of the operations.