SCAMPING TRICKS

AND

ODD KNOWLEDGE

OCCASIONALLY PRACTISED UPON PUBLIC WORKS.

CHRONICLED FROM THE CONFESSIONS OF SOME OLD PRACTITIONERS.

BY

JOHN NEWMAN, Assoc. M. Inst. C.E.,

AUTHOR OF

'EARTHWORK SLIPS AND SUBSIDENCES UPON PUBLIC WORKS';
'NOTES ON CONCRETE AND WORKS IN CONCRETE';
'IRON CYLINDER BRIDGE PIERS';
'QUEER SCENES OF RAILWAY LIFE.'

E. & F. N. SPON, 125, STRAND, LONDON.
NEW YORK: 12, CORTLANDT STREET.
1891.

PREFACE.

The following pages have been written with the view to record a few scamping tricks occasionally practised upon public works, and to name some methods founded on practical experience adopted by sub-contractors and others to cheaply and quickly execute work.

All who have had the direction or charge of an extensive or even comparatively insignificant public enterprise will agree that it is impossible for a resident or contractor's engineer to know the manner in which everything is proceeding on his division, and in some measure he is compelled to rely upon others; nevertheless, it is quite as important to ascertain that the work is carried out according to the specification and drawings as to elaborate a perfect specification and then have to partly leave the execution to the care of the beneficent fairies.

If a finger-post has been correctly pointed in the direction in which a favourable field for scamping tricks may exist, the author's object in writing this book will have been attained.

To the less experienced, the incidents and scrap-knowledge described may be more particularly useful, and on consideration it was thought that the conversational tone adopted would best expose the subject and indicate the ethics of somewhat conscience-proof sub-contractors and workmen, and also the way in which their earnest endeavours to practise the science of scamping may be exercised upon materials and under circumstances not especially referred to herein.

J. N.

London, 1891.

CONTENTS.

SCAMPING TRICKS

AND

ODD KNOWLEDGE

OCCASIONALLY PRACTISED UPON PUBLIC WORKS.

[ ]

CHAPTER I.

INTRODUCTION.

"Take this letter to my old partner as quickly as you can. Wait for an answer, and come back straight."

"All right, sir."

"Now, my wife, when my old partner arrives, leave the room. I want the coast clear as I am going to talk and have a sort of mutual confession of some tricks and dodges we have played and learned during the last forty years or so to get a bit 'extra' on the quiet; and forty years knocking about with your eyes bound to be on full glare ought to teach one a thing or two, and they have. They have! Yes; and I have been in the swim.

"Stir up the fire, if only to keep things all alike and as hot as possible; and put a couple of glasses handy, and some water and....

"So you've got back. Where is the letter?"

"Have got no letter, sir; but it is all right; your old partner will be round about 7 o'clock and will stay till he is turned out, so he said."

"Oh! I am glad."

"Why, sir, he is knocking now."

"So he is."

"Here I am, old chap, what's the matter?"

"I feel pasty, but am better now you have come. Bring your chair near the fire. Well, I want to talk to you on the quiet very badly. It will do me good, and I am sure it will not be long before the white muslin is spread over me and I'm still in death. You've come to stop?"

"Yes, as long as you like."

"That is good, and I am glad and feel better now you have said it. Before I begin, taste our home-brewed elder. It's all right, for my wife was a cook, but it's a long time ago; and between you and me, my profits don't run to providing her with as large an assortment of materials as she says is necessary to keep her fairly up to art in the cookery department."

"That is very good‌—‌the best I have tasted. Well, what is it, old partner? Shake fins."

"It's to talk over old times, and the tricks and dodges we have played, and known others do, to get 'extra' profit on the different works we have been."

"A kind of confession?"

"That's it. Don't laugh. I can't help it now."

"I understand you. Start the fun, and I will follow."

"We can talk pretty to each other, and lucky the young master is not here, for he would think that we are as bad as old Nick himself; still, we have not done many tricks for some time, and could, perhaps, put him up to a thing or two concerning the execution of work."

"Very likely; but we are all tarred with the same brush; it's only a question of quantity and thickness and what colour the paint is."

"I suppose we are bound to work up an excuse somehow or other; and if I moralize a bit tender at first, by way of a diversion, you won't mind, for it is part of the stock in trade of such rare old sharks as us, and I will cut it as short and tasty as I can.

"I was brought up right, like you; and many a time have had my shoulder patted by the good folks and been told not to think of myself too much, and to remember the feelings of others. In my salad days, you know, I used to think whether or not it was coming it rough on chaps, innocent unborn babes that will have to work in the next century, should the world hold out till then, putting in too strong work, and said to myself, Is it acting kindly towards them? No, I said, it is not treating them right to give them so much trouble to make alterations. I won't call them repairs and additions, nor improvements. I soon humbugged myself into thinking it was not being really benevolent to those who will have to work when we are all lying flat, and I hope quiet‌—‌but there, of course, such thoughts hardly make one act honestly; however, I have done moralizing now, and perhaps it ill becomes me, and I will have no more of it or it may stop my tongue. Now to business, and I am going to speak pretty freely."

[ ]

CHAPTER II.

SCREW PILES.

General Consideration‌—‌Manipulation for "extra" profit.

"You want to know my experiences with screw piles first."

"Yes."

"They do very well when the water is not deep and the ground loose sand, silty sand, or sandy fine gravel, and nothing else; and I prefer disc piles for sand, provided the water power can be easily obtained.

"The whole area of a screw blade is often taken as bearing support; but I doubt if it should be, for it is not a bared foundation‌—‌that is, one you can see and know the character of, as in a cylinder pier, for instance; but some appear to assume it is, and then claim that a lot of metal is saved and the same or more bearing obtained. The screw blade may always be right and it may not be, and no one positively knows; because no one can see whether it is down straight, turned, or broken, but the difference between the actual and the breaking strain comes to the rescue.

"Still, it is no certainty that the screw blade is resting upon the same soil, and even if it does it may not receive the load in a vertical line, and may be strained more upon one side than another. And how about the rusting of the blade, for it is thin, and seldom more than half an inch at the ends and two and a half at the pile shaft, and nearly all surface? In a cylinder pier the hearting is placed on the bared ground, and you know it is there, and it cannot rust, that's certain. I don't see the good of iron rings above a few feet higher than highest flood level, for after the hearting is set, if it be of Portland cement concrete, you can give it a coating of nearly neat Portland cement. However, we are talking about screw piles.

"I have seen screw piles screwed into soft ground for fully fifteen feet, and they seemed quite right, and yet when they were loaded they vanished. I have also known them to be twisted about something like a corkscrew, and to be impossible to get down at all when they have reached a hard layer of gravel, and nearly so when they met with a streak of hard stiff clay. Sometimes they are overscrewed, and made to penetrate somehow or other; and I remember once, when they were loaded for testing and were thought to be right, a washout occurred at one place, owing to a mistake in dredging, and the piles, although they screwed, were found to be twisted about into all sorts of shapes, and at the bottom were turned up a trifle and never went down more than a few feet, and while it was thought we were screwing them down we were screwing part of them aside. They were small solid wrought-iron piles. It is well not to forget that sand varies very much; for it is found nearly everywhere, and may be anything from large hard angular deposit that will bind, to little round mites easily blown away, and it is mixed with pretty well everything; and therefore sand is a thing you must be careful with before you take it to be just the thing for watersunk disc piles or screw piles, and you ought to know all about it. Well, assuming that it is right, and the soil will not become jammed in the screw blade, it is always advisable to try whether the sand grains will roll well together and do not wedge; for you want sand, if it is to be nice for pile sinking, just the reverse of sand for mortar or concrete, for that with round grains is the kind to screw in and not that with sharp angular grains, and if it is slimy, so much the better‌—‌just the opposite of that for mortar or concrete.

"The soil must be loose, and if it is silty so much the better. Don't undertake to screw piles into hard and compact sand, gravel, stiff clay, or where there are boulders in the ground or streaks or layers of soil of which you hardly know the character. If you do, good-bye to profit from any screwing, and may be to the screw blades, and your fishes must be got out of 'extras' by omitting a length, smashing a screw blade, or short screwing. Be careful to be paid for all piles you have screwed down directly you have done them, and take no maintenance; for I have known a ship drift, or a gale arise, and sweep away the unbraced piles like sticks, and if you are only paid when you have finished screwing a cluster of them, where are you then, and who's which? Suppose you have nearly fixed a cluster of piles, they will say you ought to have braced them at once, and you will be charged for breakages, and not be paid for having screwed them. You may talk as long as you like, and say, How could I get them all braced when the piles must be screwed separately? You will only be told that is your look-out, and that you knew the terms of the contract and must have considered any risk in the prices. So I bar injury from waves or wind, earthquakes and shakes, collisions from vessels or other floating or moving substances; and believe the last to cover all fishes, from sea-serpents, whales, porpoises, and sprats, to balloons, stray air-balls, wreckage, and mermaids; and it gives you a chance of wriggling out of squalls with an I'm-so-sorry-at-your-loss sort of countenance.

"You have to think over the staging. Fixed staging may be out of the question because of the expense; then you must either screw from the finished end of the pier as you proceed with the work, or from a floating stage, but you may not be able to get sufficient power to screw the piles from any moored floating stage. The shore piles of a pier may screw easily, but when you get out in the sea fixed staging may soon be smashed, and in that case you are compelled to do it from the end of the finished portion of the pier. There is a good deal of uncertainty, as you can judge, and you want to well consider whether and how you can get the power cheaply to screw the piles.

"The idea of the screw pile was that it should easily enter the ground and push aside any obstruction in its descent without much disturbance of the soil, with the ultimate object of obtaining, by reason of the screw blade, a strong resistance to upward and downward strain. Well, it is all right if the whole of the blade bears equally upon the soil and the earth is of the same character; but if it is not, the strain upon the screw blade is unequal, and it will sooner or later crack or break; and except in any earth like fine sand or silt and all of one kind, I should be sorry to say that the whole area of the blade does the work as I said before. And here comes in the value of an allowance of extra strength, for you cannot tell how much it has been weakened by corrosion, nor can you inspect, paint, or do anything to the screws when they are down. If I was engineer of an iron pile structure, I should have a few piles screwed at convenient places independently of the pier, but near to it, and have, say, one or two taken up every few years‌—‌say every seven or ten‌—‌just to have a look to see how matters seemed to be, and have a piece of the iron analysed, and compare it with the original analysis; and I should take care the piles were all the same quality of metal, so that the makers should not get up to fun at the foundry.

"The piles have to bear a heavy twisting strain during screwing; and take my advice, always see that the joint flanges are not light, for when piles break in screwing, they usually fail at the flanges. What I have learned shows me it is a great mistake to have the screws of very large diameter, so as to have few of them; let the blades be small rather than large, and they are best for screwing when of moderate size, and are also likely to be sounder metal. There is not the same risk of breaking them in screwing, and you may be able to screw a small blade when a big one would be smashed, and besides it is as well to have the load distributed as much as possible. A screw pile shaft should not be a thin casting because of the strain upon it in screwing, and it should be thicker on this account than a disc pile, but the latter will not do for any soils except those named before. I have known screw piles to penetrate hard and dense sand, gravel, soft sandy ground, limy gravel, loose silt, limy clay ground something like marl, stiff mud, chalk, clay, marl, and all kinds of water-deposited soil, and in almost every earth except firm rock, but it is not advisable to use them for anything much harder than fine sandy gravel, for the blades must then be strained very much and the pile and screw may be injured. It is not using them rightly, or for the purpose for which they were designed, and another system of foundations should be used except under special circumstances.

"Don't attempt to screw piles into ground having boulders in it. It is always difficult to penetrate, as also is spongy mud and stiff tenacious clay. In any ground harder than loose sand, silty and alluvial soil screwing is not easy, and you cannot say what it will cost to obtain the necessary power to screw. As regards that kind of screwing I always feel so benevolent that I like some one else to do it. Do you understand?"

"Yes; when you know a loss looks more likely than profit."

"If you like to put it that way it is not in me to object. I'm too polite. Saying 'yes' and agreeing with every one, gets you a nice character as an agreeable man, whereas you are a big fraud and a high old liar."

"Parliamentary language, please; no matter what you think."

"All right, then. You know what pure sand is?"

"You mean quite clean angular grains, and hard, too, like broken-up quartz rock?"

"Yes. Well, avoid it for screw piles, for then it is very difficult to screw them to any considerable depth. You can't displace the sand enough. It wedges and binds almost like rock."

"You mean it wedges up, and will not move?"

"That's near enough. Well, avoid clean, sharp, angular sand and shingle gravel as much as you can, and take screwing in dirty sand instead. I mean round-grained dirty sand with some clay upon it, or sandy gravel. What is wanted is something to separate the particles of the soil and act like grease so as to make them roll and not compress and become bound. You can't be too careful about this."

"I will put that down in my note-book so as not to forget it."

"To save bother, be sure to ascertain whether the work is in rough ground; and if you are abroad see that about five per cent. is allowed for breakages of all kinds, or the piles may run short.

"I have seen piles screwed into a kind of clay rock seam, the end of the pile was made like a saw, toothed, in fact, and stiffened from the bottom to the underside of the screw blade with ribs shaped to cut the ground as the pile was turned, and I doubt if they could have been screwed without. They seemed to steady the pile; but care must be taken when there is a projecting end and it is tapered to a less diameter than the pile shaft, as generally is the case, that the axis is true, or the pile will not screw vertically.

"Once I had to screw a few wrought-iron unpointed piles with a small screw blade made of angle iron fixed inside as well as the large screw blade outside. The outside blade was about 4 feet in diameter, and of half-inch plate, the inside blade projected about 3½ inches, and both blades had the same pitch; but the engineer, after having tried a few, discontinued having an inside screw, and said he thought it even arrested progress, because it interfered with the internal excavation. The experience we had with them was against their use, and they seemed to make the screwing harder, and no one was able to discover any advantage in them, although they did all they knew to flatter the novelty.

"Now a word as to cast or wrought-iron for screw piles. The question of relative corrosion can be decided at some scientific institution, and there will be hot fighting over that between the cast-iron and the wrought-iron partisans. I merely refer to screwing cast or wrought-iron screw piles into the ground. As regards the blade of the screw, it should be as stiff as possible, and therefore cast-iron is better than wrought-iron, also cheaper; and although a cast-iron screw will break easily, a wrought-iron blade will buckle and bend and give. To me, cast-iron blades seem somewhat easier to screw, if they are good clean castings. I have screwed wrought-iron piles or columns when they have been fixed to cast-iron screws, but in any case when the piles must be long, to have them of cast-iron is my wish. Solid wrought-iron piles can be obtained of a long length, but the price increases, and when they are long and of small diameter, as they must be, they are difficult to screw in a desired direction."

"What do you think of solid piles as against hollow ones?"

"Well, I heard a discussion between two engineers about it, and they agreed that solid piles only do for little or medium heights, and I asked one to write a line or two for my guidance, and this is what he dashed off. Read it."

"No. Read it to me."

"Well, it runs:‌—‌'In designing solid piles it should be remembered that the strength of solid round columns to resist torsion, torsional strength (he means strength against twisting strain) is as the cubes of their diameters, therefore a solid round bar 4 inches in diameter will bear eight times the torsional strain of a bar 2 inches, the lengths being the same.'"

"How's that?"

"Why, 2 × 2 × 2 = 8, 4 × 4 × 4 = 64, and 64/8 = 8."

"I understand."

"In the case of hollow columns, the exterior diameter must be cubed, and the cube of the interior diameter deducted from it when the relative values of different-sized columns can be compared. For transmitting motion, and here torsional stiffness is referred to, the resistance of shafts of equal stiffness is proportional to the fourth power of their diameters. A 2-inch shaft will transmit 16 times the force which would be transmitted by a 1-inch shaft without being twisted through a greater angle. When the height of the pile is considerable the diameter should be relatively larger, in order that the metal may not be subject to severe torsional strain. So don't forget the piles should be of large and not small diameter, or you may have trouble in screwing them."

"You remember old Bill Marr?"

"Rather, who did the iron pilework on the Shore Railway. I should think I did, for old Spoil'em, we called him, and I were in 'Co.' together more than once."

"Oh! you were, were you?"

"Yes. Well, there is not much to be got that way unless it is soft ground for a good depth and the piles are long and the range of tide considerable, then you may pick an odd plum now and again by a bit of useful forgetfulness. I mean this way:‌—‌By using an odd making-up length or two instead of the right length, and getting it fixed on the quiet just as the tide is rising, then you have a nice peaceful few hours in which to get the joint well covered and down before next low water; but it wants some management to keep the coast clear, and you can't do very much at it‌—‌still little fish are sweet. One day I was nearly caught at the game of 'extra' profit, and as we had only just begun, of course at the shore end, it would have been awkward for me if I had been found out, and I might have been ordered change of air and scene by the engineer. It happened like this, the piles had been going down very easily, and acting up to the principle of making hay while the sun shines, I had a couple of short lengths put on six of them. We were screwing them in triangles, so one I got to right length, and two did not find the same home, because they could not, not being long enough. I dodged the lengths so that the joints were all right for the bracing above low water. Now the road was clear, so I ordered a new length to be put on all of them before the tide turned, and that each of them was to be down 3 feet or so before the tide began falling to allow them to set, and told them that then they were to proceed as before. Now, I consider the chap that first went in for making up lengths was born right and with an eye to business and nicked profits. We were working two triangles of screw piles I thought lovely, and said, innocent-like, to my ganger, 'Get the joint of each one down say 3 feet below low-water mark so as to protect it, for no joint is so strong as the solid pile, and then you can screw them down till all the tops are level and right for the bracing.' Of course they said nothing, and I am sure never thought anything or wanted to do, too much trouble. It is not my place to teach them, either."

"No, certainly not; there you are right."

"Well, somehow or other, the ground turned hard, or we got into a streak of compact gravel. I did not trouble further about the piles after I had given orders, as the tide had started rising and the joints were well covered. It was rather an up and down shore. I felt certain in a few hours none of them could be seen except by divers, so I had a bit of business on shore which took me nearly two hours before I got back on the work. My ganger said, 'I am glad you have come back, because they stick; I have tried to get the lot down, but not one has screwed in more than a foot.' That was not exactly what I wanted, and said, 'Why, the long ones went down easily?' 'Yes,' said my ganger, 'but they were at the point of the triangle, and these others are all on one line or nearly so, and have struck hard ground.' I will cut it short, although it got exciting, for it was a race between screwing and, I might say, banging them in, and the tide that was going down; and I was clocking and measuring, and hot and cold, according as the race went, as I thought they would find me out; but I was left pretty well alone, as they cared much more about inspecting the piles than knowing how they were screwed down, besides the engineer was very busy with a lot of groynes and ticklish work improving the harbour channel. However, we just managed; but it made me feverish, and I expect the blades, if they could be seen, are not exactly as when they left the foundry; but there, there is a good deal in pilework that has to be taken on trust, it is not like a foundation you can see and walk upon if so minded. Still, screw piles are all right for some soils, but I like disc piles better for sand, those that sink by water-pressure I mean. I don't think there is the same fear of the disc being broken as there is in the case of the screw, and the sinking is so easy and soft that no parts get strained as in screwing, but the ground must be soft, or there may be a bother.

"After this shave from being bowled out, I always took care to dodge in a short one, now and then, when I knew the ground must be right, and I never got scared again. It was lucky, too, that a good many of the lengths varied, as on most jobs they are all the same, except the making-up lengths, and then down they all have to go unless a whole length can be left out when a seam of hard soil is reached, and that is not often the case, and there is not much chance of a bit of 'extras' that way on the quiet. I have known the game of 'extra' profit carried to breaking off a screw blade purposely, but I draw the line before I come to that."

"Do you? I should not have thought it, as you don't mind cutting off the heads of timber piles, so you have promised to tell me."

"That is a different material and consequently requires different treatment. You understand? Let me also tell you, I once heard a big Westminster engineer say, 'Timber we understand, iron we know a good deal about, and steel also; but we have plenty to find out yet both in the manufacture and use of nearly all metals,' or something like that, he said.

"I acted up to that; and always say to myself, We understand timber, and know how to treat it‌—‌and so I don't mind cutting it, as I know what I am about with it, although I represent unskilled more than skilled labour. Metals are different goods, and it wants skilled labour to tackle them nicely."

"There you are right."

"Yes, different goods. So, following the lead of the engineer, I leave the iron piles as delivered, as we have yet something to learn about the metal; and things that I don't know much about I avoid as much as possible, and consequently there are good grounds for getting in some short lengths as occasion offers, just to have as little to do with the material that you don't know much about and that is a bit mysterious in its behaviour. So I lessen the handling of it, and shorten the lengths, and so increase the odds against the chance of it not turning out as one thought it would; and I ought to be thanked for it, I consider. You look a bit puzzled. I tell you, you are getting thick, and want fresh pointing up to sharpen you. Listen to me. Now, suppose you buy a dozen eggs, and you think and know, on the average, at the price two are bad; you take one away and find it's bad, then you have 11 to 1 odds as against 12 to 2 or 6 to 1, and there can't be so much chance of another bad one turning up so quickly. If you don't understand my meaning I can't make you. There may or may not be a different application of explaining the egg business, but mine is what I mean you to take, and I don't intend to bother about any one else. You are younger than I thought you were, or your brain is all of a tangle."

"Wait a minute. All right. I understand now; you lessen the chances of failure and the extent of it when it occurs by having a little less to do with goods that are made of material no one seems to knows everything about."

"Now you have it. Shake fins. Glad we have worked on to the right road again, as it looked like a collision just now."

[ ]

CHAPTER III.

SCREW PILES.

Details.

"Now for some details.

"Solid piles are usually from 4 to 8 inches in diameter, and hollow cast-iron from 10 to 30 inches, and generally 10 to 20 inches. Avoid any cast-iron screw piles that are less than half an inch in thickness. When they are from 1/12th to 1/18th of the diameter is perhaps the best, according as their length is little or great; but of course they have to be of a thickness that will stand the load, and what is the best foundry practice should not be forgotten.

"Now as to the blade of the screw. If of wrought-iron, which seems to me the wrong material for that purpose, it should not be less than half an inch in thickness; if of cast-iron, as usually is the case, the thickness of the blade of the screw at the pile shaft should be about 1·25 to 1·50 that of the column, and at the edge not less than half an inch, and it should taper equally on both sides, and care be taken that the metal is the very best and so cast as to ensure uniformity and strength.

"All sizes of screws from twice to six times the diameter of the pile when hollow I have screwed, but the best are from 2 to 1 to 3 to 1, and when they are more than 4 to 1 it is to be feared they will break before they can be made to penetrate far enough to say nothing about. Solid piles with screws four to seven times the diameter of pile I have also fixed, and 5 to 1 to 6 to 1 is quite large enough; but the kind of ground and the depth to which they must be got down should govern the size and the pitch. The greatest depth, apart from imagination for measurement, to which I have ever screwed a pile is about 25 feet. Without special tackle I have made a 2 feet in diameter screw penetrate hard clay, dense sand, and other hard soil from 8 to as much as 17 feet; but then 10 to 15 feet is deep enough, for there is such a thing as overscrewing. A 3 to 4 feet in diameter screw I have fixed all depths from 10 to 20 feet in ordinary sand, clay, and sandy gravel. A 4 feet to as large as a 5 feet screw, which great size should only be used for soft soils, from 15 to 25 feet, and the most usual depth is about 15 feet, and hardly ever above 20 feet.

"A 9 feet 6 inches screw blade has been used on a 7 feet in diameter cylinder, but that is the largest I have heard of, but then it only projected 2 feet 6 inches beyond the column. Five feet is usually about the largest, and is only used for very soft soils. When more than that size they are unwieldy and very liable to be broken, and if the screws are fixed to a shaft and have to be shipped they are awkward things, and the freight becomes expensive. For hard soil, and that which will not compress nicely, about 2 to 3 feet is large enough for the diameter of the screw, and 3 to 5 feet for soft soils. The pitch of the screw is generally from one-third to one-seventh of the outside diameter of the blade. It varies according to the hardness and softness of the ground and is steeper as it becomes harder. When the pitch is increased the effect of the power applied to screw it is reduced, therefore the steeper or greater the pitch the harder the screwing.

"Piles can be screwed with a small pitch when sufficient power cannot be obtained to make a steep-pitched screw penetrate. Piles with a single turn of the screw, it seems to me, are the best, although the double-threaded screw may be right in soft marshy ground; but the usefulness of a double thread is doubtful, for I believe it breaks up the ground for no good, although some state that the screw threads work in parallel lines, and that a double-threaded screw is steadier; for they say a single-threaded pile is always likely to turn on the outside edge of the blade, and that the double-threaded is not, as it has a lip on both sides.

"Generally the screw has rather more than one entire turn round the pile, and when it is below the ground each side of the blade steadies the other, for the turns range from one to about two. Sometimes the edge of the blade is notched like a saw; but it is a question whether the saw-edge blade will screw into ground that an ordinary blade will not, and until it is proved by experiment it can only be a matter of opinion; but there is one thing to consider, a saw-cut edge blade may to some extent wedge the soil between the teeth; still, I have used them, and they penetrated thin limestone, chalk, and compact gravel seams. Instead of double threads, double points are the thing, and all screw piles should have a point of some kind. For soft ground, a single gimlet, and a double for hard soils, and I have noticed what I call a double gimlet point is best for keeping a pile in the required position, as each point prevents the other departing from a correct line. By points I mean the ends are spread out about 3 to 4 inches on each side of the axis of pile like spiral cutters.

"Unless it is certain the ground is easy and uniform, a pile with a screw having one turn to two turns for bearing purposes, and two, three, or four solid inclined screw-threads projecting about three-quarters of an inch with two end spiral cutters as just named, is my desire, or in addition to the bearing blade a single-turn thread of about 3 to 4 inches projection and the same kind of point; then unless it will screw, none will. They are less trouble when cast in one piece with the pile; but not for transport or shipping, or foreign work generally, because to be able to detach the screws is an advantage in many ways, such as packing, defects, breakages, carriage, and I think the castings are better when the blade is not cast on the pile. It may also happen that a rocky bed is unexpectedly encountered, then the pile is useless with the screw, but might be fixed firmly in Portland cement without the blade in a hole made in the rock. At the top of the screw blade seat in which a pile has to be fixed there should be a wrought-iron ring about half to three-quarters of an inch in thickness, and not less than 2 inches in width, to relieve any strain on the casting. It may be put on hot, so as to cool sufficiently tight but not strain the casting. A firm and even bearing for the pile on the socket seat is important, and it should fit accurately.

"I have heard of screw piles in which the blade was made of two or more separate segments so as to obtain, it was supposed, equal pressure all round, and to ease screwing, but rather fancy they might be inclined to jam the ground, as they would be not unlike a lot of very large round saw teeth. They may be right, but it has to be proved they will screw where a plain blade will not, provided the latter pile has double cutter-points to steady it.

"Give me a screw blade not more than about 2 feet from the points, and not one with a blade 10 feet or so above the points and say from 5 to 6 feet in the ground, for then, should the screw work at all crooked and the pile be not exactly upright at the commencement of screwing, it is no easy task to get it to stand vertically upon applying the power, because such piles are generally long and slender, and shift about until the blade is screwed. They want careful and constant guidance. Of course, the idea of placing the screw a little way down is that when the ground bears as well at that place as at the point, and there is no scour, it is no use putting the bearing blade lower. That is right; but then it always occurs to me to ask what is the use of anything below the bearing level if the foundation be protected from scour, for a thin pile by itself has little lateral strength.

"Of course, you are bound to make out a pile requires a lot of screwing or you will be considered as making too much profit, but always take care to watch how the first pile screws, and measure the distance every few minutes. What the ground is can then be judged, and you will be able to think out things for 'extra' profit. It causes me a lot of consideration sometimes, but after a struggle I generally manage to think rightly for my pocket, and work it all serene. What a beautiful sharpener of one's brain 'extras' are!

"It is not always an experimental pile is screwed so as to judge of the distance the permanent piles should penetrate, and therefore a guess has to be made from the experience of screw piles under the same conditions of screwing and in the same soil. There is a good deal of chance about it, for although the soil may be of the same general character it often varies in hardness; and that is where the bother is, for it makes the 'extras' to be wrong way about for some time. What I do then is to work the oracle, and try to make out the screw blades will be broken or injured for certain if I am compelled to screw them as ordered, and I work on the proverb that equal support is not to be obtained at a uniform depth when the ground varies, which is true; and I state that the resistance is different and offer to screw on, but say am afraid the blade may be broken, and in that how-kind-I-am-to-consider-your-interests sort of way generally manage to obtain a bit 'extra,' or save something that would have been loss, and get the pile measured at once for a making-up length, and really without damaging any one, for if the ground is harder at one place than at another there is no occasion to go so deep, always provided scour is not to be feared. So I am pleased, and it does not hurt them.

"Now for a hint or two on screwing piles. I shall not refer to the columns above the ground, but to the bearing piles below, i.e., the part that has to be screwed into the ground. However, I will just say that upon the top of some of the columns the usual hinged shoes of bearing-blocks should be placed to receive the ends of the girders, and by that means the pressure on the columns will be on the centre of the pile, and allowance be made for expansion and contraction, and that is important.

"Fixed staging is far the best from which to screw piles, but the chances must be considered of its being swept away by floods in a river, or smashed by the sea, and on any exposed coast there may not be time to construct it during the working season, so as to give a sufficient number of days for screwing operations. When a fixed stage cannot be erected, or the work be done from the end of a finished pier, pontoons or rafts are then a makeshift, but care must be taken that they do not break from the moorings. A couple of pontoons well braced together will do with a space between them to screw the pile, but in a steady or shallow river, perhaps making a timber stage upon the shore and floating it out can be done if a centre pile is fixed on the bed of the river to be certain it is in the right position when grounded. The staging must be equally weighted to make it sink, and arrangements made so that it can be floated away at any time if necessary.

"Piles can also be fixed in a medium depth of water by ordinary gantries, but if they are in the sea the road on the staging should be kept from 12 to 15 feet above high water on an open sea coast or the inclined struts and ties and rail tops as well are very likely to be destroyed, and it is also advisable to construct the flooring of the stage so that it can be easily taken away in case of storms. The stage piles also require to be well stiffened by struts, transoms, diagonals, and capping sills. I have screwed piles from a floor that has been suspended from staging by chains and ropes to the height wanted, and when lowered it was fixed temporarily and as many guides as possible were made for the piles. Perhaps as good a way as any is to fix, say four guide piles having a space between them a shade larger than the outside dimensions of the screw blade and braced to the rest of the stage, and after the screw is in position and ready for screwing in the ground, place, say a couple of frames, one at top and one as low as possible between the guide piles, about an eighth of an inch more than the outside dimension of the pile shaft, for then the pile is kept in its right position as it is screwed. The guide frames should be at about every 10 or 15 feet of the height above the ground, and at some point between the capstan level and the ground. Should it be a tidal river, fix guide booms if a properly made iron frame cannot be placed, and remember the more a pile is guided the easier it is to screw, and especially so at the start.

"The size and strength of the staging must be regulated according to the power available for screwing the piles, but the length of the lever arms and the capstan bars require a space in which to revolve, from, say, 35 to 60 feet square. No timber stage is immovable, for the wood yields. It is well to have two floors in a stage if it does not cost too much, and there is plenty of tackle and a lot of screwing to do; say, one fixed above high-water level and the other about half tide in order to obtain double power, and sufficient power to screw the piles cannot sometimes be otherwise secured. A word about floating stages. With them it is not easy to make a pile screw vertically unless the ground is uniform, and should a pile meet a boulder it will most probably be forced out of position. According to the power required‌—‌which really means the nature of the ground, as the harder the soil the harder the screwing‌—‌the form of the pile and the depth to which it has to be screwed, so must be the size and strength of the raft, pontoon, or lighter, and the moorings must hold it tightly. In some places a screw cannot be fixed from a floating stage, for the water may nearly always be too disturbed, and the pontoons may sway too much, for in all cases men, horses, or bullocks must have a steady footing, and screwing machinery also requires a firm base. Unless the moorings are very secure the platform will be unsteady. Its level should be as little above the water as practicable for work, so as to keep the point of resistance and that at which the screwing power is applied as near together as possible, and the lower the pontoon the less it rolls. It does not matter much what craft is used so long as it is broad and steady and not high, as a platform or deck must be made upon it in any case. To do any good with floating stages the power required should be little, and the ground soft and uniform, for sufficient force to screw may not be obtainable from a floating body, and in hard soil it may only be possible to screw piles a little way down and not to a sufficient depth for the load they will have to bear.

"Of course, vertical pile screwing is the easiest, and to try to screw them at a greater angle than 63°, or about ½ to 1, is unadvisable, and may not succeed, and even if they do it is too steep to be nice. 1 in 10 to 1 in 20 for raking piles is enough; for if they have to carry girder ends, the more the batter the greater the strain on the pile, and the same during screwing.

"Sometimes in loose soil it is difficult to start screwing, and then a good plan is to cast some clay or solid earth round the pitch; it steadies the pile and will probably make it bite properly, or a heavy weight placed on the pile may make it catch hold of the ground; if not, a few blows from a ram may do it. As a hollow pile penetrates, the core requires to be removed, so as to help it to descend. If it is not large enough for boys to get inside, scoops and tackle can be used. Water forced down makes sand boil round the screw blade, and when the pile is empty the unbalanced head of water outside relieves the pile and the screw blade from some of the surface friction. If water pressure cannot be used, the water inside the pile should be removed either by pumps or buckets so as to help to loosen the ground.

"Piles do not generally screw to the full pitch, but when a pile descends more than the pitch at the last turn, it can be considered the weight of the pile is too great for the ground. The slip usually increases according to the yielding or plastic nature of the soil, and the depth to which the pile is screwed. When water reaches such soils the slip is increased, but not perceptibly in sand and loose grained soils. Suppose the full pitch is 9 inches. The slip may be anything from about 1 inch to as much as 4 inches. By watching the way in which the screw penetrates, and whether it descends about the same distance each turn, or regularly decreases, it can be judged whether the bite of the screw is right. Some slip will generally take place, therefore note at first how much it is, and consider whether it will not churn up the ground, for if the screw blade turns on nearly the same lines, the bite will be gradually destroyed, and then it may be very difficult to obtain a fresh hold of the ground, and the pile will most probably not screw vertically, and the screw blade is liable to be injured and may become worn away considerably.

"Piles can be screwed by means of men, horses, oxen, and machines. Man-power can be used anywhere, machines in most places, but horses and oxen only on land when the piles are screwed on a foreshore or between tides; of course all live power works at the end of the capstan bars. Once I had the option of screwing by horses or oxen, and chose oxen. Another man had horses. I made more profit than he did, and the piles screwed easier than his. I did not let him come near me when screwing; but if you have the choice, use oxen in preference to horses. Of course, I am speaking of those countries where they are used to the yoke."

"Why?"

"Because they do not stop at any time or back like horses, not even when the resistance of the pile becomes too great without more power, but continue to pull, and therefore backward motion of the pile is prevented. The oxen were yoked to two cross-arms attached to the end of the lever.

"There are several machines for screwing piles worked by steam or other power, and when the ground is not easy to penetrate, and a large number of piles have to be screwed, their cost will be saved in the regularity, quickness, and ease in screwing, and in stiff soil by machine power I have known them screwed at the rate of 4 to 6 inches per minute. Of course, it is a special machine, and not easily sold when not further wanted except at a much less price than has been paid for it, and that has to be considered. There are several different methods of screwing piles from a fixed stage; for instance, suppose a pile of sufficient length and with the screw attached is brought to the site by barge or otherwise, the capstan head is then fixed, and the pile swung vertically over the pitch by sling-chains fastened to temporary eye-bolts passing through the bolt-holes in the flanges or otherwise, and is moved either by a jib crane, a derrick upon a raft, or some such hoisting apparatus; it is lowered into its place between the guide-piles or steadied by sling-chains or other means, then the capstan bars are put into the sockets of the capstan head, which should be at equal distances apart, and the pile is ready for screwing after it is known that it is vertical.

"Where circumstances did not allow of room for capstan bars of sufficient length for men to walk round, I have screwed piles by ropes, but it will only do when the soil is easy to penetrate. The way we worked was something like this, we had two endless ropes passing round the ends of short capstan bars and round two double purchase crabs placed upon opposite sides of the pile, about six or eight men worked at each crab, four or five winding, and two or three hauling in the slack, one rope being passed through a sufficiently deep upper slot in the capstan bar end so that it did not slip, also one in the lower slot same end. Both the taut and the slack ends of the lower and upper ropes were attached each to its own crab. A man must be stationed at the end of the capstan bars to put the slack ends of the taut and slack ropes into the slots. One rope gives the capstan half a turn when it is taut, and then it falls out of its slot and is slack, and so with the other rope, but it is not easy to keep the two ends of the rope equally tight, and the power obtained is not great and may not be sufficient. It is a kind of makeshift."

"How do you fix the capstan head to the pile shaft?"

"In many different ways. Sometimes it is keyed on or clamped tightly to the top of the pile length by steel wedges, also placed upon the pile length and fixed by temporary bolts passing through the top flanges of the pile length, and also by fixing a temporary ribbed pile into the capstan head, and by connecting it with the permanent pile by bolts or slots, and so wedging is not wanted and it can be raised and lowered. Another way is, two of the internal sides of the pile at top are cast flat for a foot or so down into which the capstan head fits, and the inside diameter is lessened for an inch or two to prevent the capstan head slipping down, but it generally can't do that, even without the narrowing of the pile for that object.

"As the capstan is subject to great wear and tear and sudden strain, it should be strong, for if it breaks the work is stopped. Wrought-iron capstan heads are used, but cast-iron are perhaps better. Sometimes the capstan sockets are made to fit the ends of rails, if rails instead of timber are used for the capstan bars, but rail bars are rather heavy and are not nice to handle. The capstan socket is generally made to receive from eight to ten or more radial lever arms, and the lengths of the bars are anything from 5 to 40 feet, but the latter is rather too long as it is very difficult to control the strain and the bar usually bends and springs. The best working lengths are from about 8 to 20 feet, if the staging is so large. The best height for the capstan bars above the floor stage is from 3 feet 6 inches to 4 feet 6 inches. The capstan bars have to be lifted and again fixed as the pile penetrates, or a temporary pile of different length has to be fixed in it, unless the capstan head can be slipped up and down on a ribbed pile, hence you may want a platform you can raise or lower easily when required. If you use double-headed rails of the same section top and bottom for the bars, you can have them bent up a little near the capstan head, and when you start, the bent end is lowest, and then the bars can be reversed and so the work proceeds.

"Put the men, horses, or oxen in the most natural position for exerting their full strength or a loss of power will result, and therefore it will cost more to screw the piles.

"Should there be gantry staging on the site, the piles can be pitched from a traverser, or by means of an ordinary crab winch. They can also be screwed from the permanent structure by means of a projecting stage temporarily fixed to it, and of a length sufficient to reach the next span. The pile is run forward upon rollers and placed in the right position. Then it is screwed on the endless rope system previously described, or by passing the rope round a deep groove in the capstan bar ends, and the rope is held tightly by being placed round a smaller grooved pulley fixed about a hundred feet or so back towards the shore. The men haul the endless rope and so the screwing is done. The worst of screwing by endless ropes this way is that the pile very probably may be pulled over towards the source of power as it comes from one direction, therefore, support is required on the side of the pile to prevent this tendency. The circumference of the ropes used varied from 4½ to 6 inches, but I have used a 10 inch rope. Small ropes are generally relatively stronger than large ones. Stretch a rope well before using, as it yields, especially hemp ropes. The distance between the point at which the power is applied, and the ground should be as little as possible. In firm sand, when the power has been more than about 20 to 25 feet above the ground, it is often very difficult to screw piles by ordinary means to more than a small depth, as two places in the pile are wanted from which to apply the screwing force, and both as low down as convenient; but in screwing from a second stage care should be taken that the pile shaft is not bent, for it may then be strained like a girder and not merely as a column, also when much power to screw is required it is not easy to avoid pulling them out of the vertical. Always screw them steadily and prevent jerking. Any obstruction, such as a boulder, tends to displace a pile, and loosens the ground around it. In soft soils it may be possible to pull piles upright by pushing aside an obstruction if the pile is given a turn or two after meeting it and before pulling; but it must be carefully done, or the pile may be smashed, and it is only safe to pull it over in easy soils and when much force is not required."

"How much power is generally wanted for screwing?"

"That is not so easily answered as asked. It varies very much, and, of course, depends upon the kind of soil and the size and pitch of the screw. Ten men may be sufficient and a single stage, but two stages may be necessary should the pile be 50 or 60 feet in length, and then not far from one hundred men. An engineer told me the force generally required for piles of usual sizes under ordinary screwing circumstances varies from about 8 to 10 tons to as much as 50 tons, and usually from about 10 to 25 tons, and, of course, the number of men to screw in proportion.

"Ordinary piles and screws have gone down 21 feet in sand in eight hours, and by steam machinery in clay at the rate of 6 inches per minute, and also, to my loss only about 1 foot in a day‌—‌and then it is time to stop altogether, should many piles hold like that. To compare what has been done with what has to be done is misleading unless the conditions are alike, for if they are otherwise the power required, cost, and rate of screwing will all be different. I have screwed a 6-inch pile with a 2-feet one-turn screw into 20 feet of ordinary sand with an applied power of 30 tons as calculated by an engineer from measurements and the force of men applied at the capstan bars. There is the surface friction on the screw blade and the pile shaft in the ground, the cutting of the earth by the edge of the blade and the points, and the loss of power from torsion and that applied compared with the effective force, slip, friction, &c., to consider; and the relative surface of the blades, width, and thickness of the cutting edge and the pitch‌—‌for a steep pitch means harder screwing. By using capstan bars and men at them, instead of ropes at the ends of the arms worked by crabs, you will find about one-fifth more power is gained, or rather is not lost. Of course, place the men as near to the end of the capstan bar as convenient for work. My lecture is finished, and I am parched."

[ ]

CHAPTER IV.

IRON PILES.

Arrangement‌—‌Driving‌—‌Sinking by Water-jet.

"Tell me what you have learned about iron pile fixing, same as you have promised me you will about timber piles."

"Very well. Here goes, then; first a word as to iron piles generally.

"Although a group of piles when properly strutted, tied, and braced have plenty of stiffness, if you have to deal with them singly they are never stiff, but they can be made steadier when getting them down by having two large pieces of wood with a half hole in them, something like the shape of the old village stocks, and by putting or lowering it at low water until it is bedded in the ground. It must be weighted though, so as to prevent it floating. It acts like a waling, and is useful when the ground is treacherous, and provided it is level.

"From watching the behaviour of piles when doing repairs and at other times, I think it wants a lot of careful arrangement to be sure the load is acting equally on the whole group, or, as may be intended, on say a few piles, and straight down the centre of each pile, for it makes a lot of difference to the strain on them, and it is not easy to make them all take the load at once as wished. It wants a good deal of attention, and the piles are not unlike a pair of horses that are not matched and don't work together properly‌—‌kind of now me, now you business. Before finishing reference to driving and screwing, let me say all the parts should be properly fitted together at the works and numbered so that the putting up on the ground is easier and in order to be certain all the bolt-holes agree; and it is well to have the lengths interchangeable and all the same, except the making-up pieces, and all bolt-holes as well as the flanges should fit in every respect.

"When columns rest on a masonry, brickwork, or concrete base the piles ought to have a ring or base-plate right round them to hold them tightly together. It lessens the pier being shaken, and saves the side pushing of the holding-down bolts. I heard an engineer say the weight of the pier above their ends should be not less than about four times any force that might tend to lift them. The anchor-plates should be well bedded upon a solid mass or the strain upon the pier may go in one direction, and that the one not wanted. Don't be afraid of bracing and strutting piles, the more of it the better. I don't think much of a single turn of a screw blade a few feet below the ground for taking a load, although some good for steadying purposes generally, because the bed may become scoured out below the blade and then the screw is no use. Therefore the depth of possible scour ought to be positively known before relying upon the blade for permanent support. A lot can be said as to the grouping of piles, whether in triangles or in rows. In a triangle, although the load upon the foundations is spread over a larger area, it does not give as much lateral strength as when the piles are placed in one row, and taking everything into consideration I think if I had six piles to put down I should not place one at the top of a triangle, two lower down, and three at the base, but have two parallel rows of three piles; besides it lessens the length of the struts and the bracing, and that is something, but, of course, each case requires to be treated in a special way, and I have noticed when doing repairs that if there are six piles fixed thus, ∴ in a triangle, the wind and other force acts principally upon the bracing between the parallel rows, and the pile at the point does not do much towards keeping the others in the right place; anyhow the bracing there does not seem to hold as tightly as it does between the parallel rows, and I have had to watch groups of them in storms, and when the sea has been high, and that is my opinion."

"Now, as to fixing iron piles."

"When the ends have to be placed in rock, which has sometimes to be done in shore pieces, 'jumping' the holes in more than about 2 feet of water is to be avoided, for if the water is not still the holes become filled with sand and drift, and you must not take the jumper out but keep on continuously making the hole. It is ticklish business, because sometimes the rock grinds the jumper, and then the wings and point wear away. Occasionally they have to be worked inside a cylinder by ropes, rods, and gearing fixed in it, the cylinder being movable and held from the end of the part of the pier that is finished, but where the water is deep the ends must be put in the rock in Portland cement by divers.

"I have driven a good many iron piles with a ram, but you have to be careful, no matter whether the soil is sand, gravel, clay, or silt. I like a copper ring on the head of the iron pile and a good long timber 'dolly,' not less than 4 or 5 feet in length, and then the ram does not burst the top. When the ground is hard the best way is to make a hole by jumpers of about 3 inches less diameter than the pile to be fixed, and in chalk soil it is doubtful whether they will go down right unless that is done; perhaps they won't drive at all, or a lot of them will be broken. I have used a ram weighing from 1 to 1½ ton for an 8 to a 10 inch pile and about a 3-feet fall, and never more than 4 feet, unless you want to deal with some old metal merchant that will give a good price for the scrap, and it does not matter how many get broken, or it is a positive advantage to break a certain quantity out of every lot, so as to have a big price for such difficult driving, and get 'extras' that way."

"I understand, no breakages deducted."

"That's it. I have driven them at the rate of fully 6 inches a minute for a few feet. They often rebound, so I had a boy with a lever, the end of it being clinched to the pile. Directly the ram fell, he gave the pile from quarter to half a turn for the first 4 or 5 feet of driving, and they scarcely rebounded at all; and he earned his wages, for I considered fully one pile extra was got down out of about every ten by the turning movement. The points require to be regulated according to the ground. From 1½ to twice the diameter or width for the length of the point is about right, but if it is made too sharp it may break. Iron piles that have to be driven are seldom more than 12 inches in width, and the thickness of the metal is generally from one-ninth to one-twelfth of the diameter. I heard an engineer say, I think it was Mr. Cubitt, experiments showed that a T-shaped cast-iron pile about 30 feet in length, should have the top of the T two and a quarter times the length of the upright part, and the thickness a twelfth of the top. Of course, the length of the pile must be considered. I doubt if you can get equally sound metal throughout when the thickness is much more than 2½ inches. From ¾ to 1½ inch is best, and piles I have broken up always seemed more even throughout about those thicknesses; but there, I suppose it is all a question of care in casting and proper machinery.

"One thing, don't drive any piles from a floating stage on the sea if you can help it, it will make you pay for the privilege; besides I have known some places where the sea was always so disturbed it could not be done, even if the moorings were as tight as you dare make them. Driven iron piles are not much seen now, and Portland cement concrete seems the fashion, and no doubt it is better. Still, iron piles can be driven in deep water without much trouble from it, and one might combine the two nicely‌—‌the iron to act as a shield to the concrete while depositing it, and give it time to set without disturbance and preserve the face."

"Have you sunk any disc piles?"

"Yes, they are all right for fine sand and silt, but you must be careful the discs are the same in form and dimensions upon all sides, or a pile will almost certainly tilt and sink crookedly. I was busy on the Lancashire coast once, and heard that Mr., now Sir James Brunlees, tried a lot of different kinds of hollow disc piles, and that the best was one with a plain flange base three times the diameter of the pile, and circular, with the bottom nearly closed, it only having a hole in it in the centre of the base 3 inches in diameter. Some ribs and cutters were cast on the bottom of the disc to break the ground up if it was hard. This is what I know about disc piles and have been put up to.

"When piles have to be sunk by water pressure, rotate the pile, and don't let it be still long, so as to lessen or prevent surface friction on the pile shaft and the sand settling round it. Always have circular discs and not too large, not above 3 feet in diameter, for they do not sink nearly so easily as the size of the disc is increased. About 2 feet discs are my choice as they go down much quicker than 2 feet 6 inches or 3 feet.

"Don't try to sink them in sand to a greater depth than 18 to 20 feet, and remember that although they may sink easily for about 12 or 15 feet, afterwards they will want some labour. When you have finished sinking piles with the water-jet, it is best to drive them down an inch or two further by a heavy ram and a very small fall, or heavily weight them as soon as possible after having done with the jet; then the disc has a bearing on firm and undisturbed ground, and if you are afraid of a blow on the pile you can have a heavy weight placed on it to help it into position and the sand to become solid. Obtain considerable pressure of water, and always cause the pile to rotate when sinking. Don't let the pressure get much below 40 lbs. per square inch, and use about 60 lbs. if you can get it. I have worked up to 100 lbs. per square inch but not beyond, and fancy there is then too much pressure, and that more sand is disturbed than is necessary. All that is wanted is to make the sand boil and remove itself from the underside of the pile and disc, but always have a few ribs or cutters on the underside of the disc as they loosen the sand as the pile is rotated‌—‌besides, should there be a strip of harder soil, it may be impossible to sink the pile without them. A rather large tube and a moderate pressure are best, and a tube not less than about 2 to 4 inches in diameter according to the size of the pile, and it is better from 3 to 6 inches, of course, if the pressure is high a larger size jet can be used, but if it is less than 2 inches it will only make a small hole, and too much below the disc, and not enough water passes through it. Try to ascertain what pressure of water makes the piles sink the easiest. Sometimes they will go down at the start as much as 3 feet in a minute, and often 2 feet, and from that to 1 foot they should do for about the first 6 or 8 feet in sand, but then the rate quickly decreases. The nozzle should be properly shaped so that the jet is whole. I mean the shape of the pipe at the place where it touches the sand. What is wanted is to get just enough force to cause the sand to separate and boil and to push it away from the disc and no further, or some of the water power is wasted, therefore a good volume of water is as necessary as a high pressure. You understand?"

"Yes."

"The tube should project about 6 inches below the bottom of the disc. A toothed tube can be fixed round it so as to help to disturb the ground and strengthen the pipe. The water supply may perhaps be obtained at a sufficient pressure from the local water-works company, then, probably, a force pump will not be required, but the pressure that can always be relied upon should be known.

"In sand, and when the water power can be easily obtained, I prefer disc piles to screw piles, because there is hardly any chance of breaking or injuring the disc; you always know where the disc is, but cannot positively say where the screw is‌—‌it may be sound and may not be; in addition, the disc is stronger than a screw blade, as it can be strengthened by ribs almost as much as one likes, and the disc in sinking is hardly strained at all compared with a screw pile. They can be sunk quicker, and do not require nearly as much plant to do it, for when you have a force pump, a guide frame‌—‌something like an ordinary pile-driving machine 25 or 30 feet in height, with a grooved pulley at top in which the chain or rope runs so that one end can be attached to the pile flange either by jaws or temporary bolts, and the other to a crab winch, which, with the guide frame, is used for lowering and keeping the pile in position, and stay the top of the guide frame by ropes to short piles driven into the ground‌—‌and a hose and two levers, with a collar to grasp the pile so as to rotate it, you have about all the special plant that is wanted.

"Of course, piles can be sunk by water pressure from a floating stage such as a barge, pontoon, or raft, so long as the pile is kept vertical, but there are the same objections to that method as with other piles. Piles are, however, got down much quicker and easier by the water jet than by screwing or driving, but the ground must be loose granular soil, such as ordinary sand.

"There is not much 'extra' to be got out of iron piles. You can only dodge a bit with a length short now and then when you have the right parties to work with, and the inspector is cross-eyed or a star-gazer, but you may get something 'extra' out of the filling them in. As usual I draw the line somewhere. Everything on earth has a boundary line. This is where I draw it. Listen!

"After as much water as possible‌—‌possible is a nice elastic word‌—‌is got out of the pile, and it is as clear of deposit as convenient‌—‌another nice easy word‌—‌and before commencing the filling, I put inside the pile everything I can get hold of that is dry, for just then I have but one way of looking at anything, and that is to consider it Portland cement concrete, unless it costs me more to use it; but when the filling is concrete, I make that as dry as mixing will allow, and sometimes hardly that. The inside of the pile is sure to be wet, and that will help the mixing. I never ram the concrete, but gently cast it in. It is only a sort of anti-rust covering, and is put in for that and to keep water out, and no weight comes upon it‌—‌it is not like the hearting of cylinder bridge piers. Ramming the concrete is not far from being a mistake, because the pile should have a chance of contracting without straining, and may be it will crack; and it is just as well to remember that although by ramming tightly you may get more solid filling and better protect the inside from rust, the pile may be strained, and it is a choice of evils, possible rust, or strain."

[ ]

CHAPTER V.

TIMBER PILES. PILE-DRIVING.

General Consideration.

"Now, as promised, I will tell you of a little bit of free trade with some timber pilework."

"That's it. I am waiting for it."

"Well, they let me have 400 feet run of pile-driving. Double row of 16 to 12 inch piles, and there were some fine sticks nearly 55 feet long, and that is a long length for a sound pile, and you have to pay for them."

"Before you begin to tell me how you scamped it, give me a hint or two about piling, and say what you have learned from experience."

"All right. First, when a pile is some distance below the bottom waling, which should be fixed as low as possible, a lot must be taken for granted, and it cannot be controlled much. I know this from drawing many piles; hundreds, I may say. After they are down about 5 or 6 feet they begin to do as they like, and take to irregular habits, and you cannot be certain the points are straight unless the ground is the same throughout, and it hardly ever is. In fact, the resistance they meet with varies, and then they accommodate themselves to circumstances; and even when the ground is very soft they turn to the line of least resistance, and if they have to be driven through several feet of soft earth to reach the solid, they may play tricks and bend about in the soft soil in go-as-you-please style, yet seem to be driving nicely; or they may stick between boulders and can't be driven further and appear to be firm as a rock, and so they may be as long as the boulders do not move, but they often do after a time, should the ground become wet, and sometimes when the next pile is being driven.

"Always be careful to see that the shoe has as large a bearing as possible for the end of the pile, and is long in the point, and more pointed as the soil is harder. Take a 12-inch pile with a 4-inch or so seat in the shoe for the stick. Well, 12 by 12 is 144, and 4 by 4 is 16, and therefore the pile end has a bearing area upon the pile shoe of one-ninth of the area of the pile. No wonder the bottom often becomes ragged and the pile shifts. The shoe should have a good hold of the timber, and be put on true to a hair, so that the point is in the exact centre line of the pile, or look out for squalls. Now high falls and light monkeys are out of fashion, and short falls and heavy monkeys are the thing, not so many piles are injured. Pushing them down is better than breaking them to bits. You should have the monkey so that its centre falls upon the centre line of the pile. The average centre of the pile should be marked on as exact as possible, and the end of the pile be cut to a template, so as to make it fit tightly to the shoe, or it may not drive straightly. I always take a lot of trouble that way and seldom have to draw a ragged one, and believe they used to drive straight. I mean from start to finish about the same number of blows and to the same depth and vertically.

"When hand-driving in soft earth‌—‌it's slow business at the best‌—‌weight the pile when the monkey is being lifted so as to stop the quivering and press it down and keep it from springing. Provided the work was of importance, and I was the Cæsar of it, before any pile was pitched ready for driving it should be inspected, its dimensions taken, it should be numbered, numbers be burnt in, and every foot from top to bottom should be marked on by a brand; and perhaps the numbers should begin at the bottom and work up, as there is not so much chance to tamper with two figures as with one, &c.

"Pile-driving is fickle work, for sometimes the piles stick because the points can't pierce the earth, and at others because they are held by friction on the surface of the piles. I have known the shoe to be cast, and the pile end look like a bass broom, and to be all in shreds. When piles split a great deal and they must be driven, the best thing to do is to get harder wood, lessen the fall and increase the weight of the monkey; same as in tunnel lining, when stock bricks are crushed, blue bricks have to be put in. The nature of the ground should govern the hardness of the wood for piles. I always pick out darkish even-coloured wood, and sniff for the resin, and the more in it the better for me. You don't catch me driving many white wood piles, for they become dry and break off short, and are not the timber for piles. Once a bother arose about some piles. There was a layer of hard gravel, and by the way the piles were driving I knew they would split, so I gave the word that Memel piles were not hard enough for such gravel; and I worked it humble like, and said to the engineer, 'I think you will agree, sir, you can't expect me to be answerable for smashing them until we get into the soft ground again. It wants rock elm or as strong timber for this soil.' After smashing a few to shreds, they supplied us with rock elm piles, and then we managed. It is true to say in the same soil the harder the pile the better it will drive, and therefore with less trouble and expense. The monkey should have an even widened-out base where it touches the pile head, so as to get the weight as near the head of the pile as possible; it also falls straighter than the long thin rams of nearly the same width throughout. Grease the ways well, and take care they are as straight as a die, and exactly vertical if it is upright pile-driving, and you'll save money. Make the blows quickly in fine-grained soil, so that it has not time to settle round the pile. In clay there is no occasion for such quick-driving, but take care to prevent the piles rebounding. Remember the same system does not do for every soil, for quick driving in hard soil sometimes smashes the piles; perhaps the earth has not had time to become displaced nicely and settle before being jammed again, and then the pile point turns and quivers and soon shreds, and cannot be driven down properly. Anyone that says piles make the ground itself firmer when they are driven into it, and so cause it to support a heavier load, will have to prove it before that can be swallowed. It is the friction on the sides of the piles that principally sustains them and not the bearing of the points. In hard soils drive slowly, for it is like chipping up a stone with a hammer. You must do it gently, or it will break the tool; and as you can't clear out the hole in driving piles, it seems to me time is required instead, so that the pressed out soil may settle away and take a bearing. I tricked a chap once pile-driving from a barge."

"How did you do it?"

"Well, it was bound to be driving from a barge or nothing, and there were three pile-drivers for us, almost as many as we could work, as the driving had to be done by degrees. Some of the work was let to a chap I did not like too much, and the rest to me. They gave me the choice of plant, so I said to the engineer, 'May I have two of the pile-drivers upon my barge, as Faggitts'‌—‌that was the other chap's name‌—‌'only wants one.' I got the two. Now Faggitts knew about driving piles on land, but had never done any driving from a barge, so I had a bit in hand of him. If you take any pile-driving and it has to be done from a barge, have more than one pile-driver on it if you have the chance; but don't place them close together, make one steady the other, and have as many as you can conveniently work at once; because, in my experience, the more you have the less the swaying, and the piles drive more regularly and the barge is steadier, and you don't have so much bother with the moorings. Of course, if the monkey does not fall flat upon the pile head the pile does not receive the full force of the blow in the right direction, the pile may be driven slightly crooked and it does not get properly treated and won't penetrate so easily, and therefore you lose money. Old Faggitts found that out in the soft soil we were driving them into. I said nothing to him, but he did to me. I never told him.

"I have read somewhere that it is wearying work going into details, but when you have to do the work yourself, unless you take care of the details you'll find they will make it hot for you; and after all, any one can speak generally, but when they have to explain in detail what they think they mean, and have to do the work themselves, they will soon find out that unless you know the details and attend to them carefully, that you won't make a profit nor anyone else. Anybody can talk tallish after about a fortnight's training, but then they have to pull up or they will fall at the next fence, which I label 'details wanted.' That's by the way, and I may have made it too strong, but it is as well to sound your engineer. No general is successful unless he knows the strength of his enemy and as much more about him as he can, and acts accordingly, and chooses his own time and place for a battle.

"Driving piles in groups, especially if the ground is soft, and not singly, is good. They go down more regularly and fit tighter, and they seem to drive quicker. I have driven cheap fir piles between elm piles that way, and a good many of the soft ones split when we had to drive them singly. Have as few key piles as possible, because they are liable to be jammed before they are down to the right depth, and then, if it is a cofferdam, it is probable a leak will occur under the key pile, because it is the easiest place for the water to soak through, and the other piles being down below it, stop the flow, and it soon finds out the short-driven key pile. When I notice a spot in a cofferdam at which water leaks through the bottom, unless it is an old stream bed, it occurs to me that the piles have not gone down properly, have got bruised, bent, turned up, or broken off, and I have found out that was the case on drawing them when the cofferdam was of no further use. Once I was ordered to drive some three-cornered piles at the turns in a cofferdam on a river front, but said, 'Square or circular shall be driven, but any other shape I will try to get down properly, provided they are carefully fitted and bevelled, but you really can't expect me to be answerable.' They deducted a fixed amount if after the piles were pitched there were more than a certain number visibly damaged or smashed, so you may depend I had a good look at the sticks before they were driven.

"I have driven piles 60 feet in length, kind of giant sticks, but 45 to 50 feet is long enough for good sound piles. Socket pile driving piecework I avoid, for the joints are ticklish business; and if a pile of ordinary length will not do, I throw out a mild hint whether the better system to use would not be Indian brick or concrete wells, or to spread out the foundations so as to get a sufficiently large bearing, or have a fascine platform, and sink it till it is firm, and test its stability properly by a load.

"There is a great deal in starting the driving correctly. I always am very careful at the start, and experiment and watch how the piles drive, and vary the fall a little until the best is known. Few considerable stretches of ground are of the same kind, and to fix a certain fall throughout is not the thing, it generally wants varying. I have easily driven piles in fine sand by having two small pipes, one each back and front, reaching a few inches below the point of the pile, and sending water down them under pressure, and by keeping the pipes on the move so that they can't be gripped. I worked out with the pipes the place where the pile had to be pitched and made a profit that way, because not only did the piles go down much quicker, and a lot of blows were therefore saved, but the piles were easier to start right. I used to call my two pipes the two bobbies, because they steered straight for their station, and these two did the same office for the piles.

"Now a word as to systems of driving; the method must suit the ground. I knew a man that believed in nothing but driving by gunpowder; he must have been going in strong for gunpowder tea, or have been in the militia, for the soil he had to do with was not homogeneous, and had boulders and other hard obstructions in it. It was not like soft sand and clay, consequently many of the piles were broken. The noise also was a nuisance in the dock, and cattle that had to be unshipped from the steamers were so unruly that they had to stop the gunpowder pile-drivers; besides, to do much good with them, a large charge is required, or it costs too much. The power necessary to work the machines is better obtained by other means, and can be without so much noise or shock.

"I have used all sorts and sizes of monkeys, from half a hundredweight to four tons, but heavy rams and short falls are the best, and steam for the power if the contract is considerable and will pay for such plant; otherwise hand, unless the piles are large and have to be driven a long way. A sixteen hundredweight monkey is about heavy enough to work nicely by hand, but it is not sufficiently heavy for a 12-inch pile, except in soft ground. For sheet piles a hand machine is good enough, for it can be moved easily, and six to eight tons weight, being about that of a steam pile-driver, costs something to shift, unless there are rails and tackle handy. Of course the blows are quicker with a steam pile-driver, and in sand that is a great point as the ground has no time to settle round a pile; but should the soil vary and be hard and soft, it is well to slow down the machine at first to lessen the fear of smashing the piles and shaking them till they tremble to destruction. I have worked a lot of different kinds of plant, and driven many piles at once, and the power was obtained from one engine giving the motion by driving bands, and in another case with drums fixed on the engine shafts, the chains being carried over sheaves to the different pile engines.

"This is my idea of pile-driving:‌—‌

"1. Steam driving. 2. Hand driving, if the piles must be driven very slowly, and there are not many to drive. 3. Never use gunpowder pile-drivers, always prefer steam, hydraulic, atmospheric, or some other motive power.

"Gunpowder is more for blowing up than anything else, in my opinion, and I know the pile shoes often shed in driving with it; that is, they loose their hold of the piles and become detached.

"A pile should penetrate regularly, and after the first few blows drive less and less, as then you have a good idea it is all right and uninjured. Uneven penetration is a proof that piles are not all right, and when they sink suddenly there is almost sure to be something wrong, and they are most likely being over-driven, shredded, frayed, shoe-cast, or split up. The rate of descent should be noted. It may be considered they are driving properly if they sink about a foot at a blow for the first one or more, and then 8 or 6 inches, and when they get down to one-eighth, one-fourth, or half-an-inch a blow for some successive blows it is time to stop and consider. I have driven piles with as few as ten blows in sand with the aid of two water pipes at work fore and aft, as mentioned before, and have had to give a pile as many as 300 blows, and when they want as many as that, with all due deference to everyone, the ground is firm enough to build upon for permanent foundations without piles. My experience goes to show that piles are often driven further than they need be, if only for use as a cofferdam, and that back struts and counterforts are better than extra depth in the ground, provided leakage is prevented. 8 to 10 feet down for solid clay, 10 to 12 feet in gravel, and about 15 feet for ordinary soils, and more care taken to ascertain the piles are where they should be, and that they are sound and whole, and not turned aside, bulged, and injured, would be my practice. In boulder ground, in my opinion, piles should not be adopted; for broken, crushed, and twisted fibre bass-broom shreds are not piles; they are out of place and should be used for clearing leaves from garden walks. The longer the piles the softer should be the ground they have to be driven into, or they shake so much, and cost more to drive.

"Unless always well buried and at such a depth that neither the moistness nor condition of the earth vary, I scarcely believe in timber pile foundations at all, except in very peculiar cases, and as a kind of aid to the main support or to help to prevent the toe of a wall from being thrust forward, but for cofferdams, jetties, piers, and such structures, of course they are useful. In hard and most gravelly soil avoid them, and also in sharp sand, if you cannot use the previously-mentioned water-pipe arrangement fore and aft; and although in ordinary clays they drive nicely, and you make a bigger profit than in sand, it puzzles me to discern what is the use of them for permanent foundations, except to help to prevent a wall sliding forward, because when a pile is driven into most clays the clay becomes tempered and softer, and a layer of concrete put in a proper distance down is better and much more certain, and distributes the load more equally. Elastic soil is bad in which to drive piles, for it yields and then rebounds. A pile will sometimes spring back almost as much as it is driven, and in such a case it is well to let the ram or monkey rest on the pile immediately after the blow is given, if you are hand-driving, or have an arrangement so that it is weighted directly each blow is delivered, and perhaps the best way is to hang heavy weights on the pile. In driving in firm sand the ground at the surface becomes considerably displaced, in clay about half as much as in sand.

"Pile-driving is different to masonry, and I always read the specification for pile work, and then judge whether and how a bit 'extra' is to be obtained, and guess as to the knowledge of those I have to deal with, and act accordingly. Sometimes a specification simply says all the piles are to be driven to the same depth or as shown on the drawings. That may be right should the ground have been tested by experimental driving, or the nature of it be known; but if not, I don't take much notice of the specification, because I hate waste, and can't afford the luxury; and it stands to reason that simply because a lot of piles are driven to the same depth they are not equally firm, nor will they support the same load unless the soil is exactly the same, and they drive well and regularly to the same depth and all nearly alike inches by inches, and this seldom occurs. Often 'extra' profit is to be had, as you will soon hear described, for when piles will not drive further than half or a quarter of an inch a blow they satisfy me they are tight enough for the purpose intended if they are at a fair depth and not wedged by boulders; but between ourselves, should a building of any kind have to be erected on piles, and anyone I really cared about had to live in it, I should always weight the piles for as long a time as possible after finishing the driving and reasonably more than the permanent load, watch the effects, and act accordingly, particularly in elastic soil.

"Remember a pile sinks less after it has rested than if it be driven continuously, therefore always take note of the set when the driving is proceeding, and not just at the start, or after an interval, although one does that for one's own benefit, and with a view to 'extras'; and no one wants to drive a pile an inch more than can be helped‌—‌at least I don't, nor have I, and it is certain never shall.

"You want to know when to stop driving. The time has arrived when a pile penetrates very little, and nearly equal for several successive blows of the heaviest ram by which it has been driven at the usual fall.

"A word as to tie and sheet piles before referring to the way I have worked piles for 'extra' profit. It is difficult to make a main pile and a tie act together, one or the other is nearly sure to have to bear more than its proper strain, and the tie rod becomes eaten by rust, bent, and loose in the piles. In taking down old banks and quays you will generally find the main pile and the tie pile are not held tightly by the tie rod, the tie pile is loose or pulled over, perhaps when first strained, and then becomes disengaged when the main pile has set to the strain. The tie rods want to be very carefully and frequently adjusted, if possible, and big washers and cleats on them are required. They hold best in firm sand, not so well in clay, and in large light loose soil, such as ashes, they are not much good. It is an impotent arrangement and it is always uncertain whether they will act together. Don't undertake to tighten up the rods. Fix the piles, and let the engineer see to the tightening up, as you may injure the piles.

"When I have to drive a lot of sheet piles, of course the piles are supplied to me, and I only take the driving. You may be sure the timber is right, and that the edges are sawn square so as to drive tightly together, and that the point is in order. I find it always pays well to temporarily place a baulk at the ground line like a waling, but not fixed to the sheet piling, as it guides the piles, lessens the shaking, and they drive easier and better. It appears to me piles cannot vibrate without force, and that is not where it is wanted, so it is wasted motion. Agitation when drawing piles is all right, but when you are driving you want it in the ground itself, and not in the piles. Once when I had to drive some thin sheet piles, I made a movable guide frame, the side against the sheet piling being planed and greased. It was like one bay of a timber-lattice bridge, and it well paid for itself as it steadied the piles.

"In taking a contract for drawing piles always find out how long the piles have been driven, for if they have been down many years they will be much harder to draw than if they have only been fixed a few months. They can be drawn by lever, hydraulic jack, and chains, and pontoons in a tide way."

[ ]

CHAPTER VI.

TIMBER PILES.

Manipulation for "Extra" Profit.

"Now, I'll tell you about a bit of 'extra' dodging that rather scared me. First, let me say, no one can ever know how much I hate waste‌—‌it can't be measured."

"You and me are alike, a couple of turtle doves on that question."

"We are. Finish up, and we will have another. I remember Lord Palmerston said, dirt was matter out of place, or something like that. Now I think piles are often good timber out of place, so I followed that lesson and said to myself 'What a lot of good timber is going to be buried; and really it is breaking and loosening the ground too much to please me, and that's a mistake, besides placing extra weight on it'; so after dwelling on the subject as much as suited me, I decided it was waste, and that it was poison to me. I had trouble on my mind about it and it made me feel thirsty and does now. Pour another out."

"There you are."

"I'm better now. Well, I wrestled over the waste question some time, and finally made up my mind not to be a party to it, it being against my principles, and, like us all, no man shall make me swerve from them, especially when they agree with my pocket."

"Certainly; shake hands. That is good!"

"Well, there was only one way to do it, so in order that every one might have their way to a certain extent I decided to drive first one pile to the depth as ordered and one to the depth that suited me, and therefore both parties were satisfied and believed they had got what they wanted; for while I left the other man, that is the engineer‌—‌excuse the disrespect‌—‌to his happy thoughts, I descended to simple practice in a way very comforting to me. Knowing it is not every pile which is driven that drives whole, or is according to drawing, many often being twisted and knocked to shreds‌—‌although I have seen them driven through a layer of old brickwork, and whole, too‌—‌and that there is a lot of uncertainty about them in some ground, I dwelt on the matter, and came to the conclusion that according to the drawings every other pile would be driven about 3 to 4 feet too far down, and that all concerned hardly agreed upon the depth to which all of them should be driven, and that I was the chief one to be considered; so I cut off a few feet of the top of nearly every other pile, and varied the length according to whether the pile happened to drive hardly or went down gently."

"Precisely."

"Somehow or other the ground seemed really grateful to me, for more of the piles were cut off than I originally intended. They must have passed the tip‌—‌may be the worms did it; anyhow the ground, after a few had been driven, seemed to become harder, and we had more sawing to do than ever. I like sawing. You see your work, and all is above board and nothing hidden and no deception. Suits our principles. Now, you are like me, you don't wish to disturb other people's minds, we are built on the lines of love too much, and tenderness is better than anger any day."

"That's it. I consider you were doing a kindness all round, or as near to it as makes no difference!"

"Well, in order not to disturb any one, it took some thinking over as to the best time to ease off the tops. I mean cut the heads off and put the rings on again, and give the tops a properly seasoned appearance. I used to call it put their hair right. Now, you know docks are not like railway works, for the men are nearly all at one place; here we were in the middle of a large town, but you'll excuse my naming the place, I am too polite to do such a thing without permission. No one was about at dinner time, for all the chaps passed the gates. The place where my work was was shut in nicely, and as there was always a row going on from the traffic close by on road and river, and loading and unloading, it was a really nice little home in which to do a bit of engineering-up-to-date."

"I understand; a convenient spot for scientific experiments in saving labour and the waste of good material."

"That's the lesson. I found dinner time was the best after a week's scouting, and that the road was clear as daylight, for all the spies were away, and there was only one that ever hung about, and he was a young engineer just come to the docks straight from Westminster. He was a nice sort of chap, and a smart one, and had the kind of face a girl looks fond upon from what I have noticed of their tricks. Of course, he did not know much of actual work, being a new pupil, I heard. By the way, what a lot of pupils to be sure some engineers turn out. I almost fancy a few of them must make as much from the schooling branch of the profession as they do from work; but let them, it is nothing to do with me, but this pupil I can say was no fool, though, the same as all new hands, the work was a novelty to him, like a new toy to a child.

"Now, the only thing to interfere with the 'extra' business as described was this pupil, so I decided to fix his attention, if I could, in another direction, and sweetly, so thought it out, and said to myself, 'You have had more difficult things to steer through than this‌—‌rather hotter, I fancy.'

"It so happened, just then, they had pulled down an old tavern, and built on the site a showy crib with balcony overlooking the river, and they had a lot of relics on view, and two nicish girls were there. Good figures, you know, and fairly on; so I made myself particularly gracious to Mr. Pupil and pointed out, submissive to his superior knowledge like, a few things on the work. Then the plot was let loose this way. I started a kind expression on my face, and said‌—‌

"'I'm afraid you find it rather rough, sir, here; there are not the nice feeding places they have in town, in fact, I think there is only one near here, sir, at all fit for you.'"

"'Where is that?'

"'It is the Anchor and Hope Hotel, sir. I can hardly direct you to it; but you have plenty of time to go there and get back fully a quarter of an hour before the men's dinner time is over, if you will allow me to show you the place, and they have almost a museum of relics of the river.'

"The relics settled it, and he took on all right, and I knew then things were working smoothly and the wind was getting round to a nice steady breeze from the proper quarter. He was a good-natured chap, and one could see liked inspecting the woman portion of creation better than works, at least, during dinner-time, and I don't blame him; some men are built that way, and can hardly say 'no' to a woman, for if they do they think they have done wrong and been unkind. Poor things! Well, we got to the place, and, fortunately, no one was in the private bar."

"You mean lobby. Don't insult the place."

"I humbly beg pardon.

"In we went, and it was lucky, for the better of the two girls was on parade; they were nieces of the landlord, so had more latitude than paid slaves. I went in first, and Mr. Pupil turned to me and said, 'I will be with you in a minute.' Now, that was just what I wanted, a word or two of priming for Polly. So after shaking hands with her, said:‌—‌

"'Polly, in a second or two a young swell will be here just new on the works, and will be on the job to the finish, three years, so make yourself pleasant as possible. Three years' presents and fun, to say nothing of odd trips out, are not to be snuffed at; and he is rich they tell me, and should be real good business all round, if you work him right.'

"She laughed; and before I could say any more the door was on the move, and in Mr. Pupil came. I kept my weather eye on him, for I can generally tell, when they run young, whether a chap is smitten sufficient. I saw the place would be a pleasant diversion, just seeing one of the tender gender occasionally, after being all day among men; so to make it appear I was a wolf on business, said, 'Please excuse me, sir, but I have to meet a gentleman at half-past twelve.'

"'Certainly. Do not let me detain you.'

"I just turned to Polly, and said, 'Show this gentleman your museum of relics, and the private room looking across the river, as I think it may perhaps suit him for an odd lunch now and then.' Polly twigged.

"I saw they were started on the road of mutual admiration, and travelling pretty, and that he meant calling again. She also seemed to like the prospect, and knew how to work the game of fascination right, and she did; so the only one in the way of preventing my doing a bit of engineering-up-to-date with the pile-driving was now removed in a nice harmonious way, and to the entire satisfaction of the company's resident engineer‌—‌no, hardly that, I mean mine. I consider I did a kind action to all parties, not excepting myself. What a blessing women are, if you use them right. Mr. Pupil had his lunch at the place every day, and Polly and he understood each other, and got on A 1, so I was told. It is soothing work bringing happiness to two young hearts as beat soft.

"Next day we started cutting off the pile-heads, while Polly and Mr. Pupil were occasionally very likely pitching their heads together so that I should not have all the fun. Well, we managed to so drive the piles after a day or two as to be able to cut off, generally during dinner time, from 2 to 4 feet, and I should think must have done over 200, when one day, just as we had nearly sawn one through, up turned Mr. Pupil. Polly and her sister were visiting, and never told me they were going, so the Anchor and Hope did not weigh-in much from him that day. My ganger, who was doing the sawing trick with me, looked a bit down, but he is not so educated as me; so I turned to Mr. Pupil and said‌—‌as he asked me what I was doing, and what was the matter‌—‌'Got the pile down wrong, sir, and shall have to lift it. I think it's broken off, or gone ragged, may be it has struck an old anchor.'

"He just looked very hard at me, nodded, and went away. It was a close shave, and lucky it was not the chief engineer. However, we had a quarter of an hour to work on that pile before the men came back, and we soon ruined it with bars and tackle. Anyhow, we raised it in no time, for we had the best tackle and everything you could wish for. We split the pile right across. It was only down 5 feet, and most of it in mud. We quickly cut it up into cleats; and out of misfortunes, between you and me, I always make as much as I can. So when Mr. Pupil returned I said to him, 'It wants a lot of experience to know when piles are not driving right, but 25 years has not been lost on me, sir, and I will have good work or none.' Perhaps 'none' would have been the correct word; but anyhow I used it coupled, and you can't complain, for if the pile had been cut there would have been none in the place where it was thought there was. We saved a lot of driving, and I said to myself, 'It is lucky this bit of wharf wall is left to me pretty well, because, as nearly most of the piles are a bit short, the wall may settle if they load it much or build on it; still I think it will settle equally, and then it won't matter so much, and they are not going to build on or near it, that I know,' so I saved nearly 1000 feet of driving on the lot; but here comes the shake. I forgot to say the piles were driven, and a platform fixed on the top for the wall in the old style, but it has gone out now, since Portland cement concrete came into fashion. One day the engineer walked over the work with two or three directors, and, after a lot of talk, they decided to build some 3-floor warehouses upon the quay, after some figuring and dwelling on it. That made me think. I heard someone say, 'The piles are 15 feet in the solid ground, and therefore will safely bear the load.' So they would if they had been, but not many hundreds of them were, and many were in 5 feet of little better than mud, and as some had been cut off 4 feet, those piles were only 6 feet in the solid ground. Understand, this wharf piling was only the beginning of a long two or three years profit for me, and I knew the warehouses would be sure to settle, and if they did unequally, over would go the show. I always avoided the quay wall afterwards; it seemed like a sort of spectre to me.

"One day the engineer sent for me to come to the office. Of course I was there sharp. He said:‌—‌

"'I want you to tell me your idea of the character of the ground upon which the western quay wall is erected?'

"Don't you think I was lucky, old pal? Here was my deliverance. It was not exactly a path of roses‌—‌there are not many knocking about now‌—‌because if I said it was soft ground he could reply, 'You had a very high price for such driving.' If I said it was firm, I felt sure, should they build a warehouse on it such as I heard them talk about, it would sink or topple over, so I had to be careful how the ship was sailed. I answered the engineer like this: 'If you'll excuse me talking to you freely, sir, I will speak my mind; but I most feel abashed with such as you, for you know a thousand times better than me.' He then said to me:‌—‌

"'Be at your ease. I wish to hear exactly what you would do in the matter if you were in my position. I have made up my mind; in fact, I have already committed my views to writing.'

"'Thank you, sir. Well, sir, I think it is a risky place, although the piles were many of them dreadfully hard to drive, and wanted a lot of care and all had it, I think, judging from the variation in the depth to which they went down under the same number of blows, that the ground is a bit mixed, and therefore I should choose another site, as there is plenty of room.'

"'Your opinion somewhat coincides with mine. Your idea, I may say, is one which the configuration of the ground leads me to think is the case without doubt. It is therefore probable that in a few days I may have a considerable length of the quay loaded with rails, nearly 2000 tons will arrive for the main and branch lines before the end of the week, as I intend to load part of the quay with about 8 tons per square foot in order to test it. In any case, much as I am urged to commence the warehouses at once, I shall not do so until the quay has withstood the test during at least a month.'

"'That is a heavy test, sir.'

"'You can go now!' He bowed, and smiled his thanks, and I withdrew. Of course, I said nothing to anyone. It don't do to annoy the guv'nor. Well, in a few days the rails came, about 2500 tons of them. The engineer sent for me again and said, 'I wish you to see the rails stacked on part of the quay in accordance with instructions you will receive.'

"I could only say, 'Very well, sir,' and withdraw. I felt I was had again, and went straight away and had a pull of rum. There was no help for it now. I was in the fix and had to get out of it somehow, and what made it doubly worse was being ordered to superintend my own ruin. Listen, for you will when I tell you I might have been tried for having killed or injured 400 men and one director! It was a near squeak for the lot, and as it was‌—‌No! I'll tell you in a few minutes what happened.

"Well, we stacked the rails over the place according to the engineer's directions, after Mr. Pupil had taken the levels‌—‌he also took them every day, to see how things were going. I made no remarks, for fear I might say something that would lead to further enquiries, and took the cue from a chap I once knew, the biggest rogue out he was; he could please them pretty, and never had any fixed opinions about anything, like some of our politicians, or could twist them about to suit the times; and he set his sails according to circumstances, so as to be pleasant to everyone, and was liked and respected by a lot that knew no better and could not see through him, but he had not a bit of honesty in him. Fact was, knowing I had got all I could out of short driving and cutting off these piles, I played a mild game of respectful bluff, more particularly as Mr. Pupil told me the ground had only gone down a mere decimal of an inch.

"One day the engineer walked over by himself and said to me, 'Come to the quay wall.'

"We got there, and I felt I had soft sawder enough in me for anything. He led off by saying, 'Although this is a severe test it is not altogether satisfactory to me. The rails shall remain in their present position for at least another month. I have known, as in cylinder sinking, subsidence to occur very suddenly and unexpectedly. I do not like the system of foundations upon piles, but have been overruled here.'

"Now what he said pleased me much, because I thought to myself if the wall does break up it will not be exactly a heart-breaking trial to him. Well, all went on as usual for a fortnight, and I heard nothing further till one Friday about 5 o'clock. It was near low water, and Mr. Pupil came to me and said the engineer wanted to see me. I went towards the office, but on the way met him and the engineer and three or four other swells, two of them that came before. I touched my hat, and walked behind. I heard the engineer say, 'Mr. Selectus, although the position is very good, I am not satisfied with regard to the foundations, more especially as I believe the ground to be varied in character; and on an old plan, dated 1720, I note a stream marked here; in fact, Mr. Pupil has searched and found a water-course existed almost from the earliest known times.'

"If he did not say exactly that, it was just like it, anyhow he spoke up pretty straight. One of the directors (I heard they were all such afterwards) said, addressing the engineer, 'I have an idea. The men will cease work, I think, very soon?' 'They will,' said the engineer. 'Have you any objection to their marching and marking time, as it were, upon the rails, as a final test, as I remember we so tested a suspension bridge I had erected at my place?'

"The engineer assented, and remarked that although the weight of 500 men was not much compared to the weight of the rails, the vibration they would create might cause a sudden subsidence. However, he slightly bowed to the director, and said, 'I leave the experiment entirely to you, although I may say it is not unattended with risk; for the test load now imposed is a very severe one for such unstable soil, and the effects of vibratory motion are usually most deleterious.'

"However, the director, after some talking, had his way, so the men were fetched. We had about 700 at work then, the company's own men. I will cut it short. Well, the director told the foreman, as the engineer asked him to do so, what he wished to be done, and the men marched up and down I should think six or seven times. It did not take long, and they soon got into step, for we had a lot of militia chaps at work; and then the director, who seemed to be enjoying himself, said, 'Now we will try three trips, double quick,' so the men went by once all on the smile, and we were as near laughing as smiling allows, when!‌—‌‌—‌

"It chokes me to think of it. Fill up the glass, so that I may keep my pipes open. Thank you, I was near being blocked up. Well, about half of the men were behind the rails, and we were all, except the director-in-command I'll call him, looking on and stationed on a mound close by. I shouted out‌—‌seemed a sort of sudden impulse‌—‌

"'Look out! the ground is settling. Run for your lives.' About half of the men heard me, and got away, but the front lot went on. I should think 200 of them. Bless you, the ground began to yaw and sink with the rails very quickly, and the wall pressed forward and toppled over in one place for about a 30-feet length with men upon the top of it, and the director as well, and fell very slowly, and quite majestically, right into the river, and there was a splash and crash. I said before it was nearly low water, and I should think there was about 5 feet on the sill and 2 feet of mud. After all, somehow or other, only about thirty men and the director were cast, and they were all taken out right, for there was plenty of assistance. Still one man had his arm broken, which was a good thing for him as it turned out, for the director made him one of his lodge-keepers; but as he was a smart-looking chap, and had been brought up right, and could not work much after, it was an even bargain."

"How about the director?"

"Ah! that's the only fun we had; for I tell you, when I saw the men and the wall go over it made me take root, and my boots were nearly pressed into the ground, and they said I went awfully white in the face. It did give me a shock; but it was lucky the break-up was so slow, for those that could not get off had time to jump and get clear of the rails, but I tell you it was a shave. As it turned out, the director had the worst ducking of the lot that fell in. He went sprawling into the mud; but he could swim, and when we saw him I nearly burst out laughing, only my feelings had been so shaken, for he was smothered in slime from head to foot, and looked like a real savage. All his hair, face, and beard were thick with mud, to say nothing of his tailoring; and I tell you he put me in mind of a baboon just then, and I don't think he will attempt any more testing.

"Of course, the warehouses were not erected upon the quay, and the engineer was not sorry at the way things had turned out. Anyhow, he let me do the clearing away the rails and the rebuilding; and I drove in the piles just the same length as the others, and nothing was said to me or suspected. It worked all right; but suppose a lot of the men had been killed, and the director as well! I tell you it was a near shave, and all before my eyes. It would just have killed me; for I should have known about another 3 feet down of those piles would have made them stand all serene. As it was, my wife said I was that disturbed in my sleep, and kicked so, that she hardly got a wink of rest, and had to double herself up in bed for fear of having her legs broken; however, it wore off in time, although once I sent myself and my old woman clean off the bedstead, and I saw by the light of the moon we were sitting on the floor, and the clothes were all of a heap close by. It made a nice picture of domestic bliss. My wife gave it me hot, and she said she would stand it no longer. I said, 'Don't grumble, you have not got to stand. You are sitting down now, and you ought to know it.' She said she heard me mumble several times in my sleep 'Cut 3 feet off her, Bill!' That was my ganger's name, and, of course, my brain was alluding to cutting off the piles; she thought it was her‌—‌no fear. Still, she always makes out I was not so good as I once was, and she felt sure Old Nick and me had night conversations. I laugh over the whole thing now. I hardly did then."

[ ]

CHAPTER VII.

MASONRY BRIDGES.

"Now I'll tell you how we got on with some masonry bridges. Being more of a scholar than most of them‌—‌thanks to the parish school‌—‌and being able to read, write, and sum a bit, I knew a trifle extra to the other chaps, and was made a ganger when very young. Somehow or other, I drifted into being crafty, and just then made friends with a man that was up to every game, and remembered old George Stephenson. He could tell and teach you something, and did me; but even I have known the time when we hardly ever had a drawing to work to, except the section, and have walked many miles behind an engineer, and heard him say to my partner‌—‌who was a mason, and a real good one‌—‌'Joe, put a bridge there, the same span and width between the inside of the parapets as the others.' 'All right, sir!'

"You know that was the time of the rush for railways, and few understood the business. Too many do now, I think, and the old country is too full of mouths generally. Then there was scarcely time to think, much more for many drawings; they were made after.

"We used to take a bridge at a time, at so much the cubic yard, and we did put it in thick, abutments, counterforts, wingwalls, and parapets, and all the work was as straight as could be made; and I have known my partner, Joe, nearly drawn into tears when he was forced by circumstances over which he had no control to own an arch to a bridge was not exactly a straight line. Spirals and winders made him that waspish as I took good care to make myself particularly wanted somewhere else than at the bridge at which he was busy when he had to do them.

"Some of the bridges we built have enough masonry in them to nearly build a church or a small breakwater, and lucky they have, as it gave one the chance of a bit of profit; and the depth of the foundations was hardly so deep as shown in the drawings made after we had built a bridge. Somehow or other our imagination used to scare away reality, and we generally were paid for a foot or more extra depth all round.

"Joe said that was the way he got his professional fees for building a bridge without a drawing, and the only way he could and, moreover, did; but he always put the masonry in solid, that is to say, when he considered it should be, although hardly, perhaps, to the specification throughout, but the face looked lovely; and if the inside work was rather rough and tumble and really "random," he knew what a good bond was, and would have it, and was really clever at selecting the right rock in the cuttings for masonry; but there, no one can expect the filling-in work to be done the same way as the facework.

"Of course, it was not exactly honest to be paid for more work than we had done; but it is only fair to say we were generous with our extra profits, and always treated the inspector and our men right. We were bound to educate them and enlighten their minds. I own it was not right, and, after all, it would want an 'old parliamentary hand' to tell the difference in dishonesty between over-measurement founded on lies and stealing. However, one is supposed to be the result of cleverness, the other, crime.

"I forgot to tell you we took a cue from a director who occasionally walked over the line, and who always showed about half-an-inch of his cheque-book sticking up out of his pocket. We were told he wore his cheque-book like the mashers do their pocket-handkerchiefs; but that he was not worth much, and was on the war path for 'plunder,' and so were we, and took his tip. I said to myself, as he has brought a new fashion into play in these parts, let us take the hint.

"'So we will,' said my partner.

"'How long is the specification for masonry?

"'I am sure I don't know. What are you talking about? I never read such things. All I want to know is for what purpose the bridge is to be erected, and whether it is to be coursed work, ashlar, or the same as the others, and up it goes according to my specification. I'm above other people's specifications, thank you. What's the use of my education if I am not? Do you think the alphabet must be again taught me?'

"'I beg pardon, partner, you are right; but appearances go a long way, and shamming is fashionable.'

"'Oh, well, have your way; we all look better when we are properly clothed; and I once heard an engineer say he never felt right when on any works without a plan in his hand, and we know a music-hall singer is generally not at home without a hat; besides, it will please them to see we have the specification always on the premises.'

"'That is what I think.'

"Well, I made two copies of it, one for Joe, my partner then, and one for me, and wrote in large letters on the top, 'Specification‌—‌masonry ‌—‌bridges and culverts.' Then we both showed the top out of our pockets, with that writing on it, in the same way the director did his cheque-book. It worked beautifully; for a few days after a big engineer came down, and we heard he had said he thought we were the smartest masons on the work, and he was pleased to see we appeared careful to comply with the specification, for he noticed we each had a copy in our pockets.

"The fun was, my partner had never read it at all; I only when copying.

"The game worked really lovely; we were looked upon as downright straight ones, and the inspector‌—‌who wanted some dodging, I can tell you, as well as a tip, now and again‌—‌was taken away and posted at the other end of the work, and then we made hay while the sun shone, and no mistake. We used to make the bridges rise out of the ground; we gave some drink to our chaps; and then, as soon as the wagons with the rock arrived from the cutting, in it went. The difficulty was to keep the face going fast enough for the filling-in work. It was a game. First a wagon-load of rock, and then‌—‌well, I suppose I must say‌—‌the mortar, but it is squeezing the truth very hard indeed. There was Joe, my partner, superintending in his own style, the raking and mortar business, and I was busy at the facework looking after our best mason.

"Give my partner his due, he was always careful about bond and throughs, and he was fond of mixing up the flat stones a bit, for he said it prevented their sliding on the beds, and always maintained that the weight above kept all tight enough and more than the mortar, so long as the stones were flat and large. I said, it's lucky it did.

"One day he frightened me. We were short of stone, owing to a mistake in the cutting, and so the facework was up a good height. At last Joe caught sight of the engine and wagons coming round the hill, and said to me‌—‌

"'Hold hard, here they come, thirteen wagons; they will fill you up both sides.'

"'I agree with you; they will, and more.'

"It was then past one o'clock, and Joe called out to me‌—‌

"'Before we leave I mean to be level with you, but you must help.'

"'Joe, it can't be done.'

"'Away with your cant's; it shall be done.'

"Well, it was tempting us too much, such a lot of rock to work on all at once; if we had only had a little more than sufficient for one day's work at a time, we could not have done what we did. By Jove, he did go it. Down came the rock‌—‌I know you will kindly excuse me from calling it building stone.

"'Easy does it, Joe, or you will burst the show.'

"'Not I,' he shouted.

"Now listen to me, for this is truth. Never since the foundation of this world did bridges grow at this rate. It beats mustard-and-cress raising and high farming into fits.

"'Smash them in, lads, bar them down; give them a dose of gravel liquor. Now then, for some real cream mortar.'"

"These, and such-like, were his war-cries."

"'Bless me, if the mortar is not as thin-placed as the powder on a girl's face, Joe.'"

"'It's pretty.'

"'Now, lads, five minutes for beer.'

"All was soon comparatively silent.

"'Joe, you must draw it milder, for the row going on is more like an earthquake let loose than anything else I can think of, and it may spoil the game, for it is bound to draw a crowd.'

"'All right, partner, I never thought of that. Talk about Jack and the beanstalk, this beats it to squash. It's lucky the rock works in flat, and is not hollow. Of course, all the stones are on their natural beds, according to the specification‌—‌understand that. Don't let us have any mistake as to the catechism; if they are not, they will grow used to their new ones and shake down to rest.'

"I've never built a bridge that fell or gave much, perhaps a wingwall has bulged, but then it is the want of proper drainage and backing and nothing to do with the masonry. We only attend to the masonry according to the specification. Chorus‌—‌According to the specification. But they all do it, as the song says.

"It's my firm conviction that the man that invented wall-plates ought to have a marble monument in his native town, for they are beautiful distributors of weight, and when the stones are small, they are salvation for such masonry as we made rise."

"I agree with you, they cover a multitude of sins, and are powerful agents in the cause of unity and good behaviour."

"That is right."

"Have a sip?"

"Yes."

"I nearly got bowled out once at the masonry game. This is between ourselves."

"Of course, we understand each other; shake hands."

"They nearly caught me."

"How?"

"We were walking over the work‌—‌when I say we, I mean a party of directors, a couple of engineers, and the resident engineer. An unlucky thing happened. Someone said, 'I should think a good view of the surrounding country is to be obtained from the top of this bridge.' Now, you know, in those days, some engineers liked offsets at the back of a wall very close together, say about every two feet, as they thought the backing remained on them, and helped to prevent the wall overturning; but it seldom does, the backing is usually drawn away from such off-sets. However, unfortunately, most of these directors had only recently returned from Switzerland, and had been up the Mortarhorn, I think they said‌—‌or thought they had, or read about it in a guide book. Anyhow, they started climbing up the back of one of the abutments. They ought to have known our work is not quite so solid as nature, nor as the Romans made in the old slow days when they were not fighting; but it is all right for the purpose intended, at least, for what we intend it, and that is enough. The abutment of the bridge I am referring to was 50 feet in length, and what must they all do but start at once at the climbing business, like a lot of schoolboys eager to get there first, and I had only time to think a moment, and to shout,

"'Be careful, gentlemen, please, the mortar has not had time to set yet, it's green.'

"Lucky, I said 'yet'; but between you and me, I should be an old one, and no mistake, if I had to wait till it set right.