The cover image was created by the transcriber, and is placed in the public domain.

THE AMERICAN
ELECTRO MAGNETIC
TELEGRAPH:

WITH THE

REPORTS OF CONGRESS,

AND A DESCRIPTION

OF ALL TELEGRAPHS KNOWN,

EMPLOYING ELECTRICITY OR GALVANISM.

ILLUSTRATED BY EIGHTY-ONE WOOD ENGRAVINGS.

BY ALFRED VAIL,

ASSISTANT SUPERINTENDENT OF ELEC. MAG. TEL. FOR THE U. S.

CANST THOU SEND LIGHTNINGS, THAT THEY MAY GO, AND SAY UNTO THEE, HERE WE ARE?—JOB.

“The same principle which justified and demanded the transference of the mail on many chief routes, from the horse-drawn coach on common highways to steam-impelled vehicles on land and water, is equally potent to warrant the calling of the electro magnetic telegraph—that last and most wondrous birth of this wonder-teeming age—in aid of the post office, in discharge of its great function of rapidly transmitting correspondence and intelligence.” Rep. of Com. of Ways and Means of H. R., 1845.

PHILADELPHIA:
LEA & BLANCHARD.
1845.

ENTERED, according to Act of Congress, in the year 1845,
By ALFRED VAIL,

In the Clerk’s Office of the District Court of the United States,
in and for the District of Columbia.

CONTENTS.

INTRODUCTION.

The propriety of presenting to the public a work of this character, seemed desirable, from the frequent calls made upon the author for some accurate and full description of the American Electro Magnetic Telegraph, which might assist to an intelligible comprehension of the principles upon which it is based, and the mode of its operations, as well as descriptions of those plans now in operation in Europe. In the execution of this task it has been his determination to spare no labour, and to omit nothing that could enable those who had never seen the operation of the telegraph, to obtain a full understanding, of the subject, and also to judge for themselves of the merit of the American invention, as compared with those of Europe. For this purpose eighty-one wood cuts are introduced to illustrate this and collateral subjects.

The various reports of Congress which have been made, from time to time, as the subject of the Electro Magnetic Telegraph has been presented to them, have been embraced in the work. They contain much information in relation to the origin and progress of the invention, as well as other useful matter. In the closing part of the work is given a synopsis of the early discoveries in electricity; the experiment of Franklin, and also the discoveries of ingenious and scientific gentlemen of the present day. The principal part, however, is devoted to a full and complete description of the various plans of telegraphic communication, by means of electricity and galvanism, in the chronological order of their invention; by which it will be seen, that for priority as well as originality, America has the pre-eminence, not only at the time of the invention, but up to the present period; nothing having yet been brought forward that fulfils so completely the conditions of what is signified by the term telegraph, as that plan invented by Professor Morse. Some of the foreign plans the author has found extremely difficult to illustrate, without almost re-inventing them, so imperfectly and obscurely have they been described.

The experimental line from Washington to Baltimore has been in successful operation for more than a year, and has been the means of conveying much important information: consisting of messages to and from merchants, members of Congress, officers of the government, banks, brokers, police officers; parties, who by agreement had met each other at the two stations, or had been sent for by one of the parties; items of news, election returns, announcement of deaths, inquiries respecting the health of families and individuals, the daily proceedings of the Senate and House of Representatives, orders for goods, inquiries respecting the sailing of vessels, proceedings of cases in the various courts, summoning of witnesses, messages in relation to special and express trains, invitations, the receipt of money at one station and its payment at the other, for persons requesting the transmission of funds from debtors, consultation of physicians, and messages of every character usually sent by mail.

The author trusts that the work will be received as one of a practical character, and furnish to those desirous to acquaint themselves with the subject, such information as they seek.

ALFRED VAIL.

Washington, D. C. August 18, 1845.

THE ELECTRO MAGNETIC TELEGRAPH.

THE GALVANIC BATTERY.

The galvanic battery, the generator of that subtle fluid, which performs so important a part in the operation of the Electro Magnetic Telegraph, is as various in its form and arrangement, as the variety of purposes to which it is applied. They all, however, involve the same principle. It is not our design here to describe the various modes of constructing it, but to confine our remarks more immediately to that used for the Telegraph.

The effects produced by the galvanic fluid upon the metallic bodies, iron and steel, exciting in them the power of attraction or magnetism, its decomposing effects upon liquids, resolving them into their simple elements, its effects upon the animal system, in producing a spasmodic and sudden irritation, are generally well known. But of the character of the fluid itself, its own essence or substance, we know nothing. In some of its phenomena, it resembles the electricity of the heavens; both find a conductor in the metals; both exhibit a spark, and both are capable of producing shocks, or when applied, cause the animal system to be sensible to them. Again, in other of its phenomena it is totally unlike it. The galvanic fluid is essentially necessary in producing the electro magnet; while the electricity of the heavens, or as it is generally termed, machine electricity, has no such power for practical purposes. The former is more dense, so to speak, and more easily confined to its conductors, while the latter becomes dissipated and lost in the atmosphere long before it has reached the opposite extremity of a long conductor. The former is continuous in its supply; while the latter is at irregular intervals. The former always needs a continuous conductor; while the latter will pass from one metallic conductor to another without that connection. The latter would not subserve the purposes required in the working of the Electro Magnetic Telegraph, and as it is neither essential nor antagonistical, its presence upon the galvanic conductors or wires, at the same time those wires are being used for telegraphic communication, does in no way interrupt or confuse its operation; and its presence is only known from the suddenness of its discharge at long intervals, accompanied by a bright spark, with a loud crack, like that of a coachman’s whip.

The most simple mode of developing the galvanic fluid is in the following manner: if a common glass tumbler is two-thirds filled with dilute muriatic acid, and a piece of bright zinc, five inches long and one inch wide, immersed in the liquid, at one of its ends, slight action will be discovered upon it. If a slip of copper be then taken, of the same dimensions, and one end immersed in the liquid, but separated from that portion of the zinc immersed, and not permitted to touch it; and the two projecting ends of the zinc and copper, above the liquid be brought in contact, an active decomposition of the muriatic acid will appear.

While the two outer ends are in contact, there is that current formed in the metallic plates, which is termed galvanic. If the contact is broken, the action ceases; if it is again renewed, the action is recommenced. Another very simple experiment, and within the power of every one to demonstrate for themselves, is that of applying a piece of zinc to the underside of the tongue, and to the upperside, a silver coin, and then by bringing their projecting ends in contact, a sensible and curious effect is experienced upon the tongue. It is a feeble galvanic shock, and is proof of the presence of that fluid termed galvanic.

We will now proceed to describe the battery used for telegraphic purposes; the same in principle, but in arrangement more complicated, and far more powerful than those in common use. Two distinct acids are employed; two metals and two vessels. Each part will be described separately, and then the whole, as put together ready for use.

First. A glass tumbler of the ordinary size is used, or about three inches high and two inches and three quarters in diameter.

Second. The zinc cylinder, made of the purest zinc, and cast in an iron mould, represented by [figure 1.]

Fig. 1.

It is three inches high, and two inches in diameter. The shell I is three-eighths of an inch in thickness. D is an opening in the cylinder, parallel with its axis, and is of no other use than to aid in the operation of casting them, and facilitating the access of the fluid to the interior. A A represents the body of the cylinder. B is a projecting arm, first rising vertically from the shell, and then projecting horizontally one and three quarters of an inch. To this arm, at C, is soldered a platinum plate of the thickness of tin foil, and hanging vertically from the arm B, as seen at O, and of the form shown in the [figure]. This constitutes the zinc cylinder and platinum plate, the two metals used in the battery.

Fig. 2.

Third. The porous cup. To avoid an erroneous impression in the use of the term porous, it will suffice to state, that it is a cup of the form represented by [figure 2], made of the same materials as stone-ware, and baked without being glazed.[1] A represents the rim surrounding the top. From the under side of the rim to the bottom, it is three inches long, and one and one-quarter in diameter. The rim projects one-quarter of an inch, and the shell of the cup is one-eighth of an inch thick. These several parts are placed together thus. The porous cup, [fig. 2], is set in the hollow of the zinc cylinder, [fig. 1], represented by H, with the rim of the cup resting upon the top of the zinc at I. The zinc cylinder is then placed in the glass tumbler. The whole is represented in [figure 3].

Fig. 3.

D represents the porous cup, F the zinc cylinder, G the glass tumbler, A the projecting arm of the zinc, C the platinum plate, and B the over-lapping of the platinum plate upon the zinc arm, where it is soldered to it. It is now in a condition to receive the acids, which are two: first, pure nitric acid, and second, sulphuric acid, diluted in the proportion of one part of sulphuric acid to twelve of water. First fill the porous cup with the nitric acid, to within one-quarter of an inch of the top; then fill the glass with the diluted sulphuric acid, till it reaches to a level with the nitric acid in the porous cup. One glass of the battery is now ready for use, and as all the other members of the battery are similarly constructed, (there being many or few, as circumstances require,) and are to be prepared and filled with their appropriate acids in the same manner, the above description will suffice. There remains, however, some further explanation in regard to the extremities of the series of glasses, that is, the mode of connecting the zinc of the first glass with the wire leading from it, and also the mode of connecting the platinum of the last glass with the wire leading from that end of the series of glasses. [Figure 4] represents their arrangement.

Fig. 4.

The glasses being all separately supplied with their acids, and otherwise prepared, they are put together upon a table, A A, perfectly dry, and made of hard wood. The first member of the series has soldered to its zinc arm a strip of copper, C, which, extending downward, has its end, previously brightened and amalgamated, immersed in a cup of mercury at N. The cup being permanently secured to the table. Then the second glass is taken, and the platinum, B, at the end of the zinc arm, is gently let fall into the porous cup, so that it shall be in the centre of the cup, and reaching down as far as its length, when the glass rests upon the table. The third glass is then taken and placed in the same manner, and so on to the last. The last glass has, in its porous cup, the platinum plate, D, soldered to a strip of copper, E, which is so constructed as to turn at the top, and admit of the easy introduction of the platinum into the porous cup, while the other end of the copper, previously prepared like the copper of the other end of the battery, terminates in a cup of mercury, P. The cup being capable of adjustment, so as to bring the platinum directly over the porous cup; is, when adjusted, secured permanently to the table. The battery, thus arranged, is ready to be applied.

THE WIRE.

The wire used in making helices for the magnets, and for connecting the telegraphic stations, is made of copper of the best quality, and annealed. It is covered with cotton thread, so as to conceal every part of the metallic surface, not so much to prevent corrosion or waste from the action of the atmosphere, as to prevent a metallic contact of one wire with another, when placed near each other. After the wire is covered, it is then saturated with shellac, and then, again, with a composition of asphaltum, beeswax, resin and linseed oil. It is now in a condition to be extended upon the poles. That portion of the wire of which the helices are made is only saturated with shellac.

THE ELECTRO MAGNET.

The electro magnet is the basis upon which the whole invention rests in its present construction; without it, it would entirely fail. As it is of so much importance, a detailed account will be given of the construction of the electro magnet, as used for telegraphic purposes. A bar of soft iron, of the purest and best quality, is taken and made into the form presented in [figure 5], which consists of four parts, viz. A F and A F are the two legs or prongs of the magnet,[2] of a rounded form, and bent at the top, approaching each other towards the centre, where the ends of each prong, without touching, turn up, and present flat, smooth and clean surfaces, level with each other at F F. The other end of these prongs or legs is turned smaller than the body, on the end of which is a screw and nut, C C. These ends pass through a plate of iron, B, of the same quality, at I and I, until they rest upon the plate at the shoulder produced by turning them smaller. They are then both permanently secured to the plate, B, by the nuts, C C, and the whole becomes as one piece. This arrangement is made for the purpose of putting on the coils or taking them off with facility. The form most common for electro magnets is that of the horse-shoe; and is simply a bar of iron bent in that form. E represents a small flat plate of soft iron, sufficiently large to cover the faces of the two prongs, F and F, presenting on its under side a surface clean and smooth, and parallel with the faces, F and F.

Fig. 5.

The coils or helices of wire, which surround the prongs, A A, necessary to complete the electro magnet, consist of many turns of wire, first running side by side, covering the form upon which the spiral is made, until the desired length of the coil is obtained; the wire is then turned back, and wound upon the first spiral, covering it, until the other end of the coil is reached, where the winding began; then again mounting upon the second spiral, covers it, and in the same manner it is wound back and forth, until the required size of the coil is attained.

Fig. 6.

The coil is wound upon a form of the size (or a little larger) of the legs of the magnet, and when the coil is completed, the form is taken out, leaving an opening in the centre, B, into which the prongs may freely pass. [Figure 6] represents a coil constructed in the manner described. A and A are the two ends of wire which are brought out from the coils. The one proceeds from the centre of the coil, and the other from the outside. C and C are circular wooden heads, on each end of the coil, and fastened to it by binding wire, running from one head to the other, around the coil. The wire used in constructing it, as heretofore mentioned, is covered in the same manner as bonnet wire, and saturated or varnished with gum shellac. This preparation is necessary, in order to prevent a metallic contact of the wires with each other. Such a contact of some of the wires with others encircling the iron prong, would either weaken or altogether destroy the effect intended by their many turns. If the wires were bare, instead of being covered, the galvanic fluid, when applied to the two ends, A and A, instead of passing through the whole length of the wire in the coil as its conductor, would pass laterally through it as a mass of copper, in the shortest direction it could take. For this reason, they require a careful and most perfect insulation. Two coils are thus prepared for each magnet, one for each prong, A and A, [figure 5].

Fig. 7.

[Figure 7] exhibits a view of the magnet; [figure 5], with its two coils, H and H, placed upon the prongs. Those parts of the magnet, not concealed by the coils, are lettered as in [figure 5], and correspond with its description. P represents the wire connecting the coil H with H, and A and A the ends of the wires leaving the coils.

We now proceed to explain the manner by which the magnet is secured upon a frame, and the arrangement of the armature, E, [figure 7], upon a lever, so that the motion peculiar for telegraphic writing may be shown.

Fig. 8.

[Figure 8] exhibits, in perspective, a view of the electro magnet and the pen lever, in a condition to show the effect of the galvanic battery upon the prongs of the magnet, F and F, and the armature, D, and the movement of the pen lever to which the electro magnet is secured. A bolt, upon the end of which is a head or shoulder, passes through the centre of the upright block, C, and between the coils, H and H, and also through the brass brace, O, projecting a little beyond it, with a screw cut upon its end. The thumb-nut, P, fitted to it, is then put on, and the whole firmly held by screwing the thumb-nut as far as possible. F and F are the faces of the iron prongs, as shown in [figure 7], presenting their flat surface to the armature, D. L is the pen lever, suspended upon steel points, as its axis, which pass through its side at X, and soldered to it. Each end of this steel centre is tapered so as to form a sharp and delicate point or pivot. E is a screw, passing through the side of the brass standard, G, and presenting at its end a sunken centre, the reverse of the steel pivot point at X. There is also another screw, similar to E, passing through the other side of the standard at G′, with a sunken centre in its end. By the extremities of these two screws, to which the tapered ends of the steel centre is fitted, the pen lever is suspended, so as delicately to move up and down, as shown by the direction of the arrow. The brass standard, G, is secured to the upright block, C. D is the armature, soldered to the end of the brass pen lever, L, separated from the faces of the magnet, F and F, about the eighth of an inch. W is a yoke, secured to the lever by a screw, and which admits through its lower part the steel wire spring, M M, for the purpose of bringing down the lever when not acted upon by the electro magnet. The spring is secured to a brass standard at the top, represented by N. R represents the three steel points of the pen,[3] which mark upon the paper the telegraphic characters; each of which strike into its own appropriate groove in the steel roller, S. T and T are the flanges of the steel roller, S, and which confine the paper as it passes between the pen points, R, and the steel roller, S, described more fully hereafter. J and I are two screws in the horizontal cross bar attached to the standard, G, and are used for the purpose of adjusting and limiting the pen lever in its movement upward and downward; the one to prevent the pen points from striking too deeply into the paper and tearing it, and the other to prevent the armature from receding too far from the faces of the electro magnet, and beyond its attraction, when it is a magnet. K is the connecting wire of the two coils H and H. A and B show the ends of the wire, one coming from each coil and passing through the stand, and seen below at a and b.

Having explained this arrangement of the electro magnet, the pen lever, and the battery; the effect of the latter upon the former will now be described. Let one of the wires from the coils, [figure 8],—a, for instance, be extended so far, that it can conveniently and securely be connected with the mercury cup, N, [figure 4], of that pole of the battery. Then take the wire b, [figure 8], and extend it also to a convenient length, so as to be freely handled, and connect it with the mercury cup, P, [figure 4], of the other pole of the battery. It will be found at the instant the connection is made, that the lever, L, [figure 8], will fly up in the direction of the arrow at W. The iron prongs in the centre of the coils, H and H, which were before perfectly free from any attractive power, have now become powerfully magnetic by the inductive influence of the galvanic current following the circuitous turns of the wire around the iron, so that now the electro magnet is capable of sustaining twenty or twenty-five pounds weight. This magnetic power concentrated in the faces of the electro magnet, F and F, attracts to it the armature or small iron, D, drawing the pen lever down on that side of its axis, and producing a reverse motion on the other side at L. Now take out the wire b from the mercury cup, and in an instant its magnetism is gone, and the lever, L, falls by the action of the spring, M. If the circuit is closed a second time, the lever again flies up; and if immediately broken, falls. In this manner it will continue to operate in perfect obedience to the closing or breaking of the circuit. If the circuit is closed and broken in rapid succession, the lever obeys and exhibits a constant and rapid vibration. If the circuit is closed and then broken after a short interval, the lever will remain up the same length of time, the circuit is closed, and falls upon its being broken. Whatever may be the time the circuit is broken, the lever will remain up for the same length of time, and whatever may be the time it continues broken, the lever will remain down for the same time. Suppose the magnet is separated at the distance of one mile from the battery; upon manipulating at the battery, at that distance, in the manner just described, the same vibratory motion is produced in all its varieties, as when they were removed only a short distance. Separate them 10 miles, and still the same mysterious fluid is obedient to the pleasure of the operator in producing the desired motion of the pen lever. If they were separated at distances of 100 or 1000 or 100,000 miles apart, the lever would doubtless obey the manipulations of the operator, as readily as if only distant a few feet. Here is exhibited the principle upon which Morse’s Electro Magnetic Telegraph is based, and which gives to the several portions of the civilized world the power of holding instantaneous communication with each other, with a rapidity far beyond what has ever before been attained. As the above explanation is given only in reference to the power of the electro magnet, when connected with the battery, and to show the movements of the pen lever, we shall speak of the arrangement of the wires for extended lines hereafter.

Having now explained the electro magnet and its operation through the agency of the battery, we will proceed to describe those various parts of the register, by which the electro magnet is made subservient to the transmission of intelligence from one distant point to another.

[Figure 9] represents, in perspective, the whole of the register, as also the key or correspondent. The electro magnet, H and H, and the pen lever, L, which have just been described under [figure 8], need not be recapitulated here. The letters used in [figure 8], represent the same parts of the electro magnet in this figure.

The brass frame containing the clock work, or rather wheel work, of the instrument, is seen at 5 and 5. The whole purpose of the clock work is to draw the paper,[4] 2, 2, under the steel roller, S, and over the pen, R, at an uniform rate.

There is also an arrangement in connection with the wheel work, by means of which the clock work is put in motion and stopped at the pleasure of the operator at the distant station. How this is done will now be explained. Upon the shaft, R′, is a brass barrel, upon which is wound the cord to which the weight, 4, is suspended, and by means of which and the intermediate wheels, the motion produced, is communicated to two rollers (not seen in this figure, [see fig. 10], E F) in advance of the steel grooved roller, S. These two rollers grasp the paper, 2, 2, 3, between them, and supply it to the pen at a given and uniform rate; the rate being determined by the adjustment of the wings of the fly, connected with the train.

Fig. 9.

Fig. 10.

We will now describe, by [figure 10], those parts connected with the wheel work, which could not be easily shown in [figure 9]. F and E represent, in outline, the two rollers which grasp the paper, 2 and 2. The roller E is connected with the train by a cog wheel upon it. F is not so connected; but is pressed hard upon E by means of springs upon the ends of the axle; S represents the grooved steel roller beneath which the paper, 2 and 2, is seen to pass. Directly under the steel roller is one of the steel pen points at R, upon the end of the pen lever; a part of which only is shown. Thus far the description given of the clock work, relates to those parts, by the agency of which the pen is supplied with paper. We now proceed to explain that part connected with the clock and pen lever, by which the clock is set in motion or stopped at the option of the distant operator.

In [figure 9], at R′, is seen a small pulley upon the barrel shaft of the clock work; at Q, is another pulley, but larger. From the pulley, R′, is a cord,[5] or band, 10, proceeding to pulley, Q, and then returning under it to pulley, R′, making it continuous. This band communicates the motion of pulley, R′, to the pulley, Q. In [figure 10], these pulleys are represented by the same letters. B represents the barrel; the arrow, the direction in which it revolves when in motion. The arrow at Q shows the direction which it takes when motion is communicated to it by R′. Part of the pulley, Q, is broken away in order to show the arm, H, soldered at the middle of the same spindle upon which is the pulley, Q, and directly beneath the pen lever, L. It is bent at D, so as to turn down and strike the wooden friction wheel, C, at the point, P. The friction wheel is secured upon the last spindle of the train at its middle and directly under the lever, L. From the pen lever, L, is seen a small rod of wire, A, passing down through the arm, H, with screw and nut under it, at I, for the purpose of shortening or lengthening it. It is permitted to work free, both at its connection with the lever and arm. This wire is also extended and passes down through the platform, where it operates upon a hammer for striking a bell, to apprise the operator that a communication is to be sent. The several parts being now explained, their combined action is as follows:

The arm, H and D, is a break, which when brought in contact with the friction wheel, C, prevents the weight of the clock work from acting upon the train, and there is no motion. By the action of the magnet, the pen lever, L, is carried up in the direction of the arrow, 3, and takes with it the connecting rod, A, and also the break, H, D. The break being thus removed from the friction wheel, C, the clock work commences running by the power of the weight. The barrel, B, must consequently turn in the direction of the arrow upon it; this motion is communicated by the band to Q, which revolves in the direction of its arrow; consequently, if the lever, L, is not still held up by the magnet, the break is descending slowly; and when it reaches P, stops the motion of the clock train, unless the pen lever continues in motion, in which case the break, D, is kept up from the friction wheel, thus permitting the clock work to run, until the lever ceases to move, when the break is gradually brought down upon the friction wheel, and the train stops. By this contrivance, the operator at a distance can so control the movement of the paper at the remote register, that when he wishes to write, it shall be put in motion, his pen be supplied with paper, and when he has finished his writing, the register shall stop.

U represents ([figure 9]) the brass standards, one on each side of the large roll of paper, 1, 1, 1, which it supports. Z is a wooden hub, upon which the roll is placed; and 12, the steel arbor of the hub, and upon which the whole easily revolves as the paper, 2 and 2, is drawn off by the clock work. Y is a brass spring, between the hub and the standard; and keeps the paper stretched between the roll and the pen.

Fig. 11.

The key or correspondent is represented by 6, 7, 8, 9. Another view of it is more distinctly seen in [figure 11]. The same letters in each, represent the same thing. V and V is the platform. 8 is a metallic anvil, with its smaller end appearing below, to which is soldered the copper wire c. 7 is the metallic hammer, attached to a brass spring, 9, which is secured to a block, 6, and the whole to the platform, V V, by screws. A copper wire passes through the whole, and is soldered to the brass spring at 6. The key or correspondent is used for writing upon the register at the distant station, and both it and the register are usually upon the same table.

Having now explained the Register, Key and Battery, we proceed to describe the arrangement of the conductors or wires connecting distant stations, and the mode by which the earth, also, is made a conductor of this subtle fluid.

The term circuit used frequently in this work, has reference to the wire, which, commencing at the positive pole of the battery, goes to any distance and returns to the negative pole of the battery. When its going and returning are continuous or unbroken, the circuit is said to be closed or complete. When it is interrupted, or the wire is disconnected, the circuit is said to be broken or open.

When a magnet or key or battery is spoken of as being in the circuit, it has reference to the use of the wire belonging to the key, magnet or battery, respectively, as a part of the circuit.

There are three modes of arranging the wires, so as to communicate between two distant stations. Two of these modes are inferior, as they furnish but one circuit for the termini, and consequently obliging one station to wait, when the other is transmitting, both stations not being able to telegraph at the same time. These two modes are called the dependent circuits. The first mode is, where two wires are used, of which [figure 12] is a diagram. B represents Baltimore, and W Washington; m is the magnet or register; k the key, and bat the battery, all at the Baltimore station; m′ is the magnet or register; k′ the key at the Washington station. The lines, represent the wires upon the poles, connecting the two stations, and are called the east and west wires. In this arrangement of the wires and also in the second, the key (which has been explained in a preceding figure, [11], and shown at 6 and 7 to be open) must be closed at both stations, in order to complete the circuit, except at the time when a communication is being transmitted.[6] For the purpose of closing the circuit at the key, a metallic wedge is used, which is put in between the anvil 8 and the hammer 7, and establishes the circuit. Supposing the battery is in action, and B has a communication for W: he opens his key, by removing the wedge, and sends his message. The galvanic fluid leaves the point, P, of the battery, and goes to k, to m, along the east wire to k′, to m′, and back by the west wire to N pole of the battery. In the same manner it proceeds along the wires, if W is writing to B. In this arrangement, the direction of the galvanic current is the same, whether B or W is communicating, unless the poles of the battery are reversed.

Fig. 12.

Fig. 13.

The second mode has but one wire and the ground, represented by [figure 13]. The use of the ground as a conductor of the galvanic fluid, between two distant points, is to many a mystery. But of the fact there is no question. The above diagram exhibits the manner in which the east wire and ground were used from the first operation of the Telegraph, until the close of the session of Congress, June, 1844. In this diagram, we will minutely follow the course of the galvanic current. B represents Baltimore, and W Washington; C represents a sheet of copper, five feet long and two and a half feet wide, to which a wire is soldered and connects with the N pole of the battery. This sheet of copper lies in the water at the bottom of the dock, near the depot of the Baltimore and Ohio Rail Road, Pratt street. From P of the battery, the wire proceeds to k, the key, then to m, the magnet or register, then it is the east wire to k′, the key at W, then to m′, the magnet or register, then to the copper sheet, C′, buried beneath the brick pavement in the dry dust of the cellar of the capitol. The direction of the current is from P of the battery to k, to m, and along the east wire to k′, to m′, and to C′, where it is lost in the earth; but reappears at the copper plate, C, at B, and thence to the N pole of the battery, having completed its circuit. It is, therefore, certain, that one-half of the circuit is through the earth. From B to W the east wire is the conductor; and from W to B the ground is the conductor. In this arrangement, the west wire is thrown out, and is no part of the circuit; while the earth has been made a substitute for it.

Fig. 14.

The last diagram, as has been stated, exhibits the plan of the wire and ground, as used for telegraphic purposes, from its first operation, until the adjournment of Congress in 1844, being prevented from completing the arrangement of the third mode from the throng of visitors, that pressed to see its operation. After the close of the session, the following arrangement of the wires was made, as shown in the diagram, [figure 14], by means of which, both stations could transmit at the same time, with one battery for both, and the keys were not required to be closed. It is called the two independent circuits. Here the west wire is used for transmitting from B to W; and the east wire from W to B. The copper plates at B and W remain as they are described in the second plan. Bat, the battery, at B is used in common for both circuits. It is simply necessary here to designate the course which the fluid takes when both lines are in operation, viz. B transmitting to W; and W to B. In the former case, the current is from P of the battery to k, then the west wire, then to m′, at W, then to C′, thence through the ground to C at B, and then to the N, or negative pole of the battery, as shown by the arrows. In the latter case, the current is from P of the battery to m, then the east wire, then to k′, at W, thence to C′, thence through the ground to C at B, thence to the N, or north pole of the battery, as shown by the arrows. This arrangement, by which one battery is made efficient for both circuits at the same time, where two were formerly used, was devised by Mr. Vail, assistant superintendent, in the spring of 1844, and has contributed much to diminish the care and expense in maintaining that part of the apparatus of the telegraph. One battery being now used instead of two. By the above diagram, it will be perceived that the ground is common to both circuits, as well as the battery, and also the wire from the N pole of the battery, to the copper plate, C; and from the copper plate, C′, to the junction of the two wires near the two arrows. For the purposes of telegraphic communication they answer as well as though there were four wires and two batteries. Instead of using the ground between C and C′, a wire might be substituted, extending from the N pole of the battery to the junction of the wires at the two arrows at W. The arrangement of the wires, battery, keys, magnets or registers at both stations, with the ground, as shown in [figure 14], is the plan now used for telegraphic operations between B and W; and has many decided advantages over the arrangements of figures [13] and [14]. First. In both of those arrangements, the circuit is obliged to be kept closed, when neither station is at work; and as the battery is only in action when the circuit is closed, it follows that the battery will not keep in action as long as when the circuit is allowed to remain open, as in the use of the third plan, [figure 15]. Second. There is an advantage in dispensing with the use of the metallic wedge, which is liable to be forgotten by the operator. Third. The attendant may occasionally leave the room, and is not required to be in constant waiting, as the clock work is put in motion and stopped by the operator at the other end, and the message written without his presence. But in the first and second arrangement, the apparatus for putting in motion and stopping the clock work, is entirely useless. The attendant being obliged to put it in motion and stop it himself.

We will now proceed to describe the modus operandi of transmitting intelligence from one station to another; the arrangement being as in [figure 14]; k is the key of the operator at Baltimore, and m′ represents his register, or writing desk, at Washington; k′ is the key of the operator at Washington, and m his register, or writing desk, at Baltimore. Each has the entire control of his respective register, excepting, only, that each operator winds up the other’s instrument, and keeps it supplied with paper. It will also be borne in mind, that each circuit is complete, and everywhere continuous, except at the keys, which are open. If, then, the hammer is brought in sudden contact with the anvil, and permitted as quickly as possible to break its contact by the action of the spring, and resume its former position, the galvanic fluid, generated at the battery, flies its round upon the circuit, no matter how quick that contact has been made and broken. It has made the iron of the electro magnet a magnet; which has attracted to it the armature of the pen lever; the pen lever, by its steel pen points, has indented the paper, and the pen lever has, also, by the connecting wire with the break; taken it from the friction wheel; this has released the clock work, which, through the agency of the weight, has commenced running, and the two rollers have supplied the pen with paper. But, as only one touch of the key has been made, the clock work soon stops again, if no other touches are made, by the action of the break upon the friction wheel.

This shows the whole operation of the Telegraph, in making a single dot by a single touch of the key. In order now to explain more fully the operation of the steel pen points upon the paper, which is in contact with the grooved roller, let there be made four touches at the key; this will be sufficient to start the clock work, and allow the paper to have attained a uniform rate; then let six touches be made at the key. The contact has been made six times and broken six times. Each time it is closed, the electro magnet, as heretofore explained, attracts to it, with considerable force, the armature of the pen lever, carrying up the steel pen points against the paper, 2, under the steel roller, S. The three points of the pen, falling into the three corresponding grooves of the roller, carry the paper with them and indent it,[7] at each contact. There then appear upon the paper, as it passes out from under the rollers, six indentations, as if it had been pressed upon by a blunted point, such as the end of a knitting needle would be supposed to make, when pressed upon paper, placed over a shallow hole, but in such a manner as not to pass through the paper, but raising the surface, as in the printing for the blind. These indentations of the paper are the marking of the pen, but varied in the manner now to be described.

By examining the telegraphic alphabet, the characters will be found to be made up of dots: short and long lines—and short and long spaces. A single touch of the key, answers to a single dot on the paper of the register; which represents the letter, E. One touch of the key prolonged, that is, the contact at the key continued for about the time required to make two dots, produces a short line, and represents T. A single touch for about the time required to make four dots, is a long line, and represents L. A single touch for about the time required to make six dots, is a still longer line and represents the 0 of the numerals. If the use of the key be suspended for about the time required to make three dots, it is a short space, used between letters. If suspended for the time required to make six dots, it is a long space, used between words, and a longer space is that used between sentences. These are the elements which enter into the construction of the telegraphic characters, as used in transmitting intelligence. The alphabet is represented by the following combination of these elements.

ALPHABET.

Suppose the following sentence is to be transmitted from Washington to Baltimore:

It is evident, as the attendant at Baltimore has no agency in the transmission of this message from Washington, his presence, even, is not absolutely required in the telegraph room at Baltimore, nor is it necessary, previously, to ask the question, are you there? The operator at Washington transmits it to Baltimore, whether the attendant is there or not, and the telegraphic characters are distinctly recorded upon the paper of the Baltimore-register. If he omits a letter at the key, in Washington, it is omitted on the paper in Baltimore. If he has added at the key in Washington, it is also upon the paper in Baltimore, nothing more or less is marked upon it.

Specimen of the Telegraphic Language.

• ·· -· - ···· · ·· ·· · ·- · ·· ·--· -···· ···-·
• ··-·· · · -· -- ·· ·· ···- · · ·· ·· ·- --· · ····
• · · -- ·· ·-· · ·· · · -- · ··- · ·· · · ····· · -
• ···· · · — · ·· · - · ·· ·· ·· · ·- — · ·-··
• ····· · · ·· ·· -- · -· - · · ·-· ·-· · ·· ·- -· -·-
• — ·· -· ··- ····· · · -· ·- ·-- ·· · ·· · ···
• · · -- · ····- -- ·· — · ··· ·· -· — · -· --·
• - ···· ·-- ·- ··· ·· · ·- ··· ··- ·- — — ·· ··
• · ·· · ·· · ·- — — · -·· - · · -- ·· ·· -- ·
• -· -·· ·· -· ·- ·· · · · -· ···- · · ·· ··· ·- -
• ·· · · -· ·-- ·· - ···· ·--· · · ·-· - ···· ·
• ····· ·- ··· ··· · -· --· · · ·· ··· ·· -· ·-- ····
• ·· ·· · ···· · ·-·· ····· · · ·· ·· -- · -· - ·· -
• ·-- ·- ··· ·- ··· ·· · · · ·· - ·- ·· -· · -·· -
• ···· ·- - - ···· · · — · ·· · - · ·· ·· ·· · ··
• - ·· ·· - · ·· ·- ···- · — — · -·· - ···· · ··
• · · ··- --· ···· - ···· · ·-- ···· · · — · ·· ·
• ·· · ·· ·· · ··- ·· - ·· -· ·- - ·· -- · -·
• · · - ·- ····· ····· · ·· · ·· · ·· ·- -··· — · -···
• ··- - ·- ····· ····· ·- · ·· · -· - — ·· ·· ·· -·
• ··· - ·- -· - ·- -· · · · ··- ··· ·· - ·· -- -- ·
• -·· ·· ·- - · — ·· ·· · · ·· · ·· · ··- · ·· · ·· ·
• -·· - · · -- · - ···· ·- - ·· ·-· - ···· ·
• ····· · ·· · ··· · -· ·· · · · · ·-· · — · ·· · -
• · ·· ·· ·· · ·· - ·· ·· ·· · · · ··- — -·· -··· ·
• -- ·- -·· · ···- ·· ··· ·· -··· — · ·· -· ·- -·
• ·· ·· -·· · ··· ·· · ·· · -·· ····· ·- · ·· - · ·
• ·-· - ···· ·· ··· ·· · ·· · ·· ·· · ··- ·· - ·· -
• ·-- · · ··- — -·· -· · · - -··· · -·· ·· ·-· ·-·
• ·· ·· · ··- — - - · · ·· · · · -· ··· - · ·· ··-
• ·· · - ·- ··· ·· ·· ··· - · -- · · ·-· ··· ··
• --· -· ··· -··· ·· ·· ·-- ···· ·· ·· · ···· ·· -·
• - · — — ·· --· · -· ·· · · ·· · · · ··- — -··
• -··· · ·· -· ··· - ·- -· - ·- -· · · · ··- ··· —
• ·· ·· - · ·· ·- -· ··· -- ·· - - · -·· - ···· ·
• - ···· · · ··- --· ···· - - ···· ··- ··· ·· · · · -·
• ·· · · ·· ···- · -·· - · · · · -·- ··· - · ·· · ·
• -· --· ···· · · — -·· · · ·-· -- ·· ·· -- ··
• -· -·· ·· -· - ···· · — · ·· ··· ··- · ··· ·--
• ···· ·· ·· · ···· - ···· · ···- · · ·· ·· ·- --· ·
• ·- ·-· ·-· · · · ·· -·· · -·· · ··· ·· ····· —
• ·- -· -· · -·· ·- ··· ·· ·· ··· - · -- · · ·-·
• ··· ·· --· -· ··· · ··· ·- -· ·- ····· ····· ·- · ··
• ·- - ··- ··· - · · ·· · ·- · ·· · ·· ·· ·· ·· - ··
• -· - · · · ·-· ·-· · ·· · - ·· ·· · ·- ··· - ·-
• ··· ····· · ·· · ·· · ··· · · ·-· - ·· ·· ····· ·
• ·-- ···· ·· ·· · ···· ·· ···· ·- -·· -·· · ···- ··
• ··· · -·· ·-· · · · ·· - ···· ·· ··· ····· ··-
• · ·· ····· · · ··· · - ···· · ·-· ·· · ·· ··· -
• ·-- · · -·- ·- ·-· - · · ·· -- ·· ·· ·- · ·· · ··
• ·· ···- ·- — ···· · · -- · · ··· ·- — - ····
• · · ··- --· ···· - ···· · · ·· · ··· - · · ·-· -
• ···· · -- ·- ·· · ···· ·· -· · · ·· ·· ·· ·-- ·- ···
• ····· — ·- -· -· · -·· ·· ·· · - ·-· · ·· · · --
• - ···· · ····· · ·· · ··· ··· ··- · ·· · · · ·-· ··-
• -· ·- ···- · · ·· -·· ·- -··· — · -·· ··- - ·· ·
• ··· ·· ·-- ·- ··· ·· · · · -- ····· · — — ·
• -·· - · · ····· · · ··· - ····· · · -· · -- ·· ··
• · ·-·· ····· · · ·· ·· -- · -· - ··· · ··· ·-- ·-
• ··· -· · · - ·- -··· — · - · · - · ··· - -
• ···· · ·-- ···· · · — · ····· — ·- -· ··- -·
• - ·· — ·-- ·· - ···· ·· -· ·- ·-· · ·-- ·-- · ·
• -·- ···
• ··· ·-· -··· -- · · · ·· ··· ·

From the peculiarity of the motion obtained at the pen lever by the action of the battery upon the electro magnet, it is evident that a few elements only are presented upon which to base the telegraphic characters. The motion of the lever, to which is attached the steel pen points, is vibratory; but capable of being so controlled as to cause it to retain either of its positions (that is, up or down) as long, and at such intervals, and in as quick succession as the operator may choose. Therefore, every sort of combination which dots, lines and spaces, in any succession, and of any length can make, are here as much at the pleasure of the telegraphic manipulator, as the English alphabet is with the letter writer. So that if from this countless variety, twenty-six of the most simple, to represent letters, and ten to represent the numerals, shall be taken, we come at once into possession of the means of representing words and sentences, by new, but intelligible characters, and through them, can be conveyed as clearly, and as concisely, as if they were given viva voce, or written in Roman characters. Such is the alphabet given above. This conventional alphabet was originated on board the packet Sully, by Prof. Morse, the very first elements of the invention, and arose from the necessity of the case; the motion produced by the magnet being limited to a single action.

During the period of thirteen years, many plans have been devised by the inventor to bring the telegraphic alphabet to its simplest form. The plan of using the common letters of the alphabet, twenty-six in number, with twenty-six wires, one wire to each letter, has received its due share of his time and thought. Other modes of using the common letters of the alphabet, with a single wire, has also been under his consideration. Plans of using two, three, four, five and six wires to one registering machine, have, in their turn, received proportionate study and deliberation. But these, and many other plans, after much care and many experiments, have been discarded; he being satisfied that they do not possess that essential element, simplicity, which belongs to his original first thought, and the one which he has adopted. A detailed account of these various plans with fewer or more wires, might be given here, but it will suffice merely to present the alphabet adapted to a register, using 2, 3, 4, 5, or 6 wires, with a separate pen to each wire capable of working together, or in any succession. It is obvious that every additional pen will give an additional element to increase the combination, and were there any real advantage in such an arrangement it would have been adopted long since.

[No. 1.]

No. 2.

No. 3.

No. 4.

No. 5.

CORRESPONDENT OR KEY.

The modes of manipulation for sending intelligence, which at various times have been invented by Prof. Morse, are more various than any other part of the machinery of the telegraph. A few of them will now be described. The first method, invented as early as the year 1832, was that of using a type, resembling saw-teeth, set up in long frames, and made to pass under a lever, by means of machinery, at a uniform rate, for the purpose of closing and breaking the circuit, in a manner hereafter to be described. The following figure, [15], represents the saw-teeth type. The top of the narrow tooth corresponds with the dots of the letters, and the long tooth, with the lines of the letters. For instance, A, has one tooth for a dot, and a long tooth for a line, which is the telegraphic letter A; then follows a space at the end of the type, corresponding with the short space between two letters.

Fig. 15.

Fig. 16.

These type were set up in a cavity, made by putting two pieces of long rules of brass plate together, side by side, with a strip of half their width between them; so as to make the cavity sufficiently large to receive the type. This was denominated the port rule, and is represented in [figure 16] by A A. Parts of the type are seen rising above the edge of the rule, and below it are seen the cogs, by which, with the wheel, V, the pinion, L, and the crank, O, the port rule, with its type, were carried along at an uniform rate in a groove of the frame, K, R, under the short lever, C, which has a tooth, or cam, at its extremity. J is a support, one on each side of the frame, for the axis of the lever, B and C, at its axis, I; a and i are two brass or copper mercury cups, fastened to the frame. These cups have the negative and positive wires soldered to them, N and P. D and H are the ends of one copper wire, bent at right angles at that portion of it fastened to the lever, B. The ends of the copper wire are amalgamated, and so adjusted, that when the lever is raised at C, by the action of its cam, passing over the teeth of the type, the lever, B, is depressed, and the wires, D and H, dip into the mercury cups, and thus complete the connection. This plan worked well, but was too inconvenient and unwieldy.

The second method was upon the same principle, with a more compact arrangement. The type being put into a hopper and carried one by one upon the periphery of a wheel, the teeth acting upon a lever in the same manner as in the [figure preceding]. The wheel being horizontal.

Fig. 17.

The third plan differed only in one respect, instead of the types moving in a circle, they were made to move in a straight line. [Figure 17] represents that instrument. The type were all made with small holes through their sides, so as to correspond with the teeth of the wheel, A, driven by clock work and weight. K is the side of the frame containing the clock work. B is the hopper containing the types, with their teeth outward. The hopper is inclined at an angle, so that the type may slide down as fast as one is carried through the cavity, a and b. C is a brass block to keep the type upright, and sliding down with them. E and F are two small rollers, with springs (not shown) to sustain the type, after the wheel, A, has carried them beyond its reach. G is a lever for the same purpose as C in [figure 16]. D its support, through which its axis passes. I′ is the long lever, O, of the left side figure, to the end of which, is the bent wire in the mercury cups, H and S, and to which are soldered the wires, P and N. T is the spring to carry back the lever, O. F′ is one of the small rollers, and G′ the short lever. At R may be seen a part of one of the type passing; the tooth having the short lever upon its point, thereby connecting the circuit at the mercury cups, H and S, by the depression of the long lever, O. The hopper, B, may be of considerable length, and at a less angle. When a communication is to be sent, it is set up in type, and put in the hopper. The clock work is then put in motion, and the wheel, A, will carry them down one by one. In this manner, the cam on the end of the lever, G, will pass over all the teeth of the type, as in the plan shown by [figure 16].

The fourth plan was by means of keys, one for each letter and numeral. By pressing upon any one of the keys, it wound up the clock work of the instrument. The key being instantly released, and returning gradually to its former position, produced the closing and breaking of the circuit required to write its character upon the register.

The fifth plan is in some respects similar to the last, but much more simple, and requiring less time in transmitting intelligence. [Figure 18] exhibits a view of the keyed correspondent, with its clock work. A′ represents a top view of it, and B′ is a side or front view. 1 1 1 1, of both views, represent the long cylinders of sheet brass, covered with wood or some insulating substance, except at the black lines, which represent the form of the letters, made of brass, appearing at the surface of the cylinder and extending down and soldered to the interior brass cylinder. A cross section of the cylinder is seen at D′, of which the blank ring is the brass cylinder, and the blank openings to the outer circle the metallic forms of the letter J, and the shaded portion of the circle represents the insulating substance, covering the whole surface of the cylinder, except, where the letter-forms project from the interior. It is obvious that every letter and parts of each letter are in metallic connection with the brass cylinder. At each end of the cylinder is a brass head, with its metallic journal, and the journal or arbor turns upon its centre in a brass standard, 17, secured to the vertical frame. To this standard is soldered the copper wire, N, connected with the negative pole of the battery. There are together thirty-seven letters and numerals upon the cylinder, and made to correspond to the letters of the telegraphic alphabet. To each of these, there is a separate key, directly over the letter cylinder. Each key has its button, with its letter, A, B, C, D, &c., marked upon it, and beneath the button in a frame of brass, is a little friction roller. The key is a slip of thin brass, so as to give it the elasticity of a spring, and is secured at the thicker end by two screws to a brass plate, extending the whole length of the cylinder, so as to embrace the whole number of keys. This plate is also fastened to the vertical mahogany frame. At the right hand end of the brass plate is soldered a copper wire, leading to the positive pole of the battery, after having made its required circuit through the coils of the magnet, &c. It is clear, that if any one of the keys is pressed down upon any portion of a metallic letter, that the circuit is completed; the galvanic fluid will pass to the brass plate to which, P, wire is soldered; thence along the plate to the spring or key; then to the small friction roller beneath the button; then to that portion of any letter with which it is in contact; then to the interior brass cylinder, to the arbor; then to the brass standard, and along the negative wire, soldered to it, to the battery. We have now to explain in what manner, the cylinder is made to revolve, at the instant any particular key is pressed, so that the metallic form of the letter may pass at an uniform rate under the roller of the key; breaking and connecting the circuit so as to write at the register, with mechanical accuracy, the letter intended.

Fig. 18.

Fig. 19.

4 4 is the platform upon which the parts of the instrument are fastened. 3 3 is the vertical wooden back, or support, for the keys and brass standard, 17. 2 is the barrel of the clock work contained within the frames, 5 5. With the clock work, a fly is connected for regulating its motion, and a stop, a, for holding the fly, when the instrument is not in use; 6 is a very fine tooth wheel, on the end of the letter cylinder; 7 is also a fine tooth wheel, on a shaft driven by the clock train. In the front view is seen, at 9, another fine tooth wheel, suspended upon a lever, the end of which lever is seen at 8, [figure 18], A′. 18 is a stop, in the standard, 17, to limit the return motion of the cylinder, which also has a pin at 18, at right angles with the former. 16 is a small weight, attached to a cord, and at its other end, is fastened to the cylinder at b. The relative position of the three fine tooth wheels, and the lever, 8, are better seen in a section of the instrument, [figure 19]. The same figures represent the same wheels as in the other views, A′ and B′. 7 is the wheel driven by the weight and train. 6 the wheel, on the end of the cylinder, to which motion is to be communicated, and 9 is the wheel, suspended upon the end of the lever, 8, of which 10 is its centre. 1 1, is the brass lettered cylinder. 11 and 13 the buttons of the two keys, one a little in advance of the other. 14 is the spring and the two friction rollers of the key, may be seen directly under the buttons. 15 is the stop pin. 16 the small weight and cord attached to the cylinder, to bring it back after each operation. 4 4 is the end view of the mahogany platform. The arrows show the direction which the wheels take, when the lever is pressed with the thumb of the left hand at 8, so as to bring wheel 9, up against 7 and 6, connecting the two, as shown by the dotted lines. Wheel, 7, communicating its motion to 9, and 9 to 6, which causes the metallic letters to pass under the rollers in the direction of the arrow. Now, in order to use the instrument, let it be supposed a letter is to be sent. The stop, a, [figure 18], A′, is removed from the fly, and the clock work is set in motion by the large weight. Then the thumb of the left hand presses upon the lever, 8, at the same time, key, R, is pressed down by the finger of the right hand, so that the small roller comes in contact with the cylinder. At the instant the roller touches the cylinder, the letter begins to move under the small roller, making and breaking the circuit with mechanical accuracy. When the letter has passed under the small roller, the thumb is taken off the lever, 8, and the finger from the key, R. The cylinder is then detached from its gear wheel, 9, and the weight, 16, instantly carries it back to its former position, in readiness for the next letter. Then the lever, 8, and the key, E, are pressed down at the same instant for the next letter, and it is carried under the small roller in the same manner as the first, which, when finished, the wheel, 9, is suffered to fall, and the cylinder returns to its natural position again. The same manipulation is repeated for the remaining letters of the word.

In the following figure, [20], is represented the flat correspondent. It somewhat resembles the keyed correspondent, but without keys or clock work. A represents the arrangement of the letters, presenting a flat surface. Those portions in the figure, marked by black lines and dots, represent the letters which are made of brass. That portion which is blank, represents ivory or some hard insulating substance, surrounding the metal of the letters. As in the keyed correspondent, each letter and parts of each letter extend below the ivory and are soldered to a brass plate, the size of the whole figure, A. A sectional view of this is seen at 1 1, which is ivory, and 2 2, the brass plate below. The whole is fastened to a table, B. 5′ and 5′ is a brass plate, called the guide plate, with long openings, represented by the blanks, so that when the guide plate, 5′ 5′, is put over the form, A, each opening is directly over its appropriate letter, and is a little longer than the length of the letter. 4′ and 4′ is the wooden frame, to which the guide plate is secured. The ends of this frame are seen in the sectional [figure] at 4 4, and the guide plate at 5 5. The dark portions of which, represent the partitions, and the blanks the openings. It will be observed here that the plate, 5 5, resting upon the wooden frame 4 4, is completely insulated from the brass letter plate 1 1, and 2 2. The blank space between them showing the separation. It is, however, necessary that the guide plate should be connected with one pole of the battery, and the letter plate with the other pole. For this purpose a brass screw, F, passes up through the table, B, and through 4, into the guide plate 5 5. The head of the screw has a small hole through it, for passing in the end of the copper wire, G, from the battery, and a tightening screw below, by which a perfect connection is made. At D, is another screw, passing through the table, and into the letter plate, 2 2. To the head of this screw is also connected another copper wire, E, extending to one of the poles of the battery.

Fig. 20.

This instrument, when used, occupies the place of the key or correspondent, in the description heretofore given of the register. The circuit is now supposed to be complete, except, between the guide plate, 5 5, and the letter plate, 2 2. Now, if a metallic rod, or pencil, C, be taken, and the small end passed through one of the openings in the shield, above the letter, its point will rest upon the ivory; and if it be gently pressed laterally against the side of the opening of the guide plate, at the same time a gentle pressure is given to it upon the ivory, and then drawn in the direction of the arrow, 4′, it is obvious, that when the metallic point reaches, for instance, the short line of letter B, the circuit will be closed; and the fluid will pass from the battery along the wire to the screw, F, then to the guide plate, along the plate, to the rod, thence to the metallic short line of letter B, thence to the letter plate below, thence to the screw, from the screw to the wire, and thence to the battery. When the point has passed over the short metallic line, it reaches the ivory, and the circuit is broken, then, when it comes upon the first metallic dot, it is again completed, and in the same manner the circuit will be completed and broken, until the point has passed over the whole of the letter. The use of this instrument requires great uniformity of time or speed in drawing the point over the letter form. The steel point of a common ever-pointed pencil is frequently used in place of the pointed rod, C.

The seventh plan is that heretofore explained as being now in use, of which there are several varieties. This mode of writing requires that the operator should be perfectly familiar with the alphabet, as he is obliged to spell the word, and measure the time, required by the various parts of each character making the letter. It might seem difficult, yet experience has proved it to be superior to every other method yet devised. By this method, intelligence is transmitted faster than it can be written down by reporters; and after a little practice, with so perfect a formation of the characters, that mechanical accuracy can alone be compared to it. As this is the simplest in its construction, it will doubtless supercede all the others. We will now give its simplest form.

[THE LEVER KEY.]

This, as we have said, is the most simple form of the key, or correspondent. It is a modification of that shown at [figure 11]. The following figure, [21], represents a key, where the lever is taken advantage of to make a more perfect connection, with less application of power. A key of the above form has been used during the past winter for reporting the proceedings of Congress, and has been found to operate with ease, with certainty, and with great rapidity. A A is the block or table to which the parts are secured. E represents the anvil block. J the anvil, screwed into the block, both of brass. B is another block, for the stop anvil, K, and the standard for the axis of the lever C. L is the hammer, and is screwed into the lever, projecting downward at V, almost in contact with the anvil, J. R is another screw of the same kind, but in contact with the anvil, K, when the lever C is not pressed upon. Under the head of each of these two screws, are tightening screws, which permanently secure the two hammers, to any adjusted position required for the easy manipulation of the lever, C. D is a spring which sustains the arm of the key up, preventing the hammer, L, from making contact with the anvil, J, when not in use. G is a screw connecting with the brass block, B, and F a screw connecting with the block, E. To these screws the two wires, I and H, of the battery are connected. Now, in order to put it in operation, it is necessary to bring the hammer, V, in contact with the anvil, J, for so long a time, and at such regular intervals as are required by the particular letters of the communication. When the key is pressed down, the fluid passes from the battery to the wire, H, then to the screw, G, then to the block, B, then to the lever, C, at the axis, S, then to its metallic anvil, J, then to its screw, F, then to the wire, I, and so to the battery.

Fig. 21.

The circuit of the Electro Magnet, closed and broken by the movement of the lever itself, acted upon by the Electro Magnet. Showing the rapidity with which it is possible to close and break the circuit.

In order to give some idea of the rapidity with which the circuit may be closed and broken, and answered by the motion of the lever, a figure, [22], is here introduced to explain its construction and arrangement. The platform is shown at T, and the upright at S, to which the coils of the electro magnet, A, are secured by a bolt with its thumb-nut, E. D a projecting prong of the soft iron, and C the armature attached to the metallic lever, B, which has its axis or centre of motion at K, in the same manner as the electro magnet of the register; R being the standard through which the screws pass. O is the steel spring secured to R, by a plate, U, upon it, and the screw, N. L and M are adjusting screws, for the purpose of confining the motion of the lever, B, within a certain limit. P is a wire with an eye at the top, through which the end of the steel spring passes, with a hook at the other end, passing through the lever. The wire, Q, from one of the coils is connected with the plate, U, at the top of the standard, R. As the standard, R, is of brass, the plate U, the axis of the lever of steel, and the lever, B, of brass, all of them being metals, and conductors of the galvanic fluid, they are made in this arrangement to serve as conductors. I is the wire proceeding from the other coil, and is extended to one pole of the battery. The wire, H, coming from the other pole, is soldered to the metallic spring, J, which is secured to the upright, S, by means of the adjusting thumb screws, F and G. This spring is extended to J, where it is in contact with the lever, B. We have now a complete circuit. Commencing at I, which is connected with one pole of the battery, from thence it goes to the first coil; then to the second; then by Q to U, the plate; then to the standard, R; then to the steel screw, K; then to the steel axis; and then to the lever to the point, J; where it takes the spring to H, the wire running to the mercury cup of the other pole of the battery.

Fig. 22.

The battery being now in action, the fluid flies its circuit; D becomes a powerful magnet, attracting C to it, which draws the lever down in the direction of the arrow, X. But since B and J are a part of the circuit at V, and since, by the downward motion at X, and the upward motion at V, the circuit is broken at J, the consequence is, that the current must cease to pass, and D can no longer be a magnet. Hence the lever at V returns, coming again in contact with J. Instantly the fluid again passes and the lever at V separates from J. Again the fluid ceases to pass, and the lever again returns. By this arrangement, then, the lever breaks and closes the circuit, and it does it in the best possible manner to show how rapidly the magnet can be made and unmade. When its parts are well adjusted, its vibrations are so quick that no part of the lever is distinctly seen. It appears bounded in size by the limits of its movement up and down, and the motion is so rapid as to produce a humming noise, sometimes varying the notes to a sharp key. In this way it will continue to operate so long as the battery is applied. We infer from this, the almost inconceivable rapidity, with which it is possible to manipulate at the key of the register in sending intelligence, far surpassing that of the most expert operator. This arrangement of the electrome, was devised by Mr. Vail in the summer of 1843.[8]

CONDUCTING POWER AND GALVANIC
ACTION OF THE EARTH.

After the close of the session of Congress in the spring, 1844, a series of experiments were commenced by the request of Prof. Morse, under the direction of Mr. Vail, for the purpose of ascertaining what amount of battery was absolutely required for the practical operation of the telegraph. From the first commencement of its operations to the close of the session, so anxious were the public to witness its almost magic performances, that time could not be taken to put it in a state to test either the size of the battery required, or bring into use all the machinery of the register. On that account, but one wire was used during that period for transmitting and receiving intelligence, and the capabilities of the instrument were shown to some disadvantage; requiring the constant attendance of those having charge of the two termini.

This first experiment made was to ascertain the number of cups absolutely required for operating the telegraph. Eighty cups had been the number in use. Upon experiment, it was found, that two cups would operate the telegraph from Washington to Baltimore. This success was more than had been anticipated and urged on further experiments, which eventually proved that the earth itself furnished sufficient galvanic power to operate the electro magnet without the aid of a battery. In the first experiment, a copper plate was buried in the ground, and about three hundred yards from it, a zinc plate was also buried in the ground. To each of these plates a wire was soldered, and the ends brought into the telegraph office, and properly connected with the key and electro magnet of the register. The battery not being in connection. Upon manipulating at the key, it was found that the electro magnet was operated upon and the pen of the register recorded. This led to another experiment upon a more magnificent scale, and nothing less than that of using the copper plate at Washington, and the zinc plate at Baltimore, with the single wire, connecting those distant points, and the battery thrown out. Here, too, success followed the experiment, though with diminished effect. By the application of a more delicate apparatus the Electro Magnet[9] was operated upon, and the pen of the registering instrument recorded its success. From these experiments, the fact appears conclusive, that the ground can, through the agency of metallic plates, constantly generate the galvanic fluid.

Six Independent Circuits, with six wires, each wire
making an independent line of communication.

Fig. 23.

In the above figure, [23], let the right hand side represent Washington, and the left, Baltimore. The lines marked 1, 2, 3, 4, 5, and 6, between m and k, respectively, represent the six wires connecting (for example) Washington with Baltimore. Each cluster of black dots, P and N, represent the batteries of that line upon which it is placed. There are three batteries at W, and three at B; m 1, m 3, and m 5, represent the three magnets, or registers, and k 2, k 4, and k 6, the three keys, or correspondents, at Baltimore; k 1, k 3, and k 5, are the three keys, or correspondents, and m 2, m 4, and m 6, the three magnets, or registers, at Washington. C B is the copper plate at Baltimore, and C W, the copper plate at Washington, one at each terminus.

In order to operate the six lines, simultaneously, if required by the pressure of telegraphic communications, there must be three operators at each station, commanding their respective keys, and presiding at their respective registers. If the three operators at Washington choose to write in Baltimore, together, or in succession, on their respective registers at the latter place, the galvanic current of the three lines 1, 3, and 5, takes this direction. Commencing at the point, P, of the three batteries, 1, 3, and 5, at W, it passes to k, of the keys; thence along the wires to m, the magnets, 1, 3, and 5 at B; thence to the single wire, where the three currents join in one to C B, the copper plate; then through the ground to C W, the other copper plate; then up the single line to their respective batteries at the point, N, having each finished its circuit independently of each other.

If, in reply, the three operators at Baltimore wish to write upon their registers at Washington, either together, or in any succession, they may choose; the fluid leaves the point, P, of their respective batteries, at Baltimore, 2, 4, and 6; unite in the single wire to C B, the copper plate; then pass through the ground in the direction of arrows to C W, copper plate at Washington, then along the single wire to their respective magnets, m, 2, 4, and 6; then along the extended wires to k, 2, 4, and 6 at Baltimore; and then to N pole of their respective batteries. In this manner six distinct circuits may be operated independently of each other, at the same time, or in any succession, with only one wire for each, and the ground in common, as a part of the circuit.

It is obvious from the above arrangement that if one wire only, extended between two distant points, will suffice to enable communications to be exchanged with each other; that any number of wires extended, will also, each, individually, give a distinct and separate line for telegraphic purposes, independently of all the other lines on the same route.

Fig. 24.

In [figure 24], the same arrangement of wires is observed as respects their number, and the situation of the keys and magnets; but, with this difference, that instead of six batteries, one for each wire, there is but one, which is placed upon the single wire, with which the six wires join. The battery is represented by four black dots, marked N B P. The course of the fluid in this case is from P to C, the copper plate on the left side; then through the ground to C, the copper plate on the right; then through the single wire to any of the six wires, which may be required, then to the single wire on the left side to N, of the battery. It is obvious that in this arrangement there is a division of the power of the battery, depending upon the number of circuits that may be closed at any one instant. For example: if circuit 1 is alone being used, then it is worked with the whole force of the battery. If 1 and 2 are used at the same instant; each of them employ one-half the force of the battery. If 1, 2 and 3 are used, then each use one-third its power. If 1, 2, 3 and 4, then each circuit has one-fourth the power; if 1, 2, 3, 4 and 5 are used, at the same moment, then one-fifth is only appropriated to each circuit, and if 1, 2, 3, 4, 5 and 6, then each employ a sixth part of the galvanic fluid generated by the battery.

MODE OF SECRET CORRESPONDENCE.

The great advantage which this telegraph possesses in transmitting messages with the rapidity of lightning, annihilating time and space, would perhaps be much lessened in its usefulness, could it not avail itself of the application of a secret alphabet. We will now proceed to describe some of the various systems by which a message may pass between two correspondents, through the medium of the telegraph, and yet the contents of that message remain a profound secret to all others, not excepting the operators of the telegraphic stations, through whose hands it must pass.

For this purpose let the telegraphic characters representing particular letters be transposed and interchanged. Then the representative of a, in the permanent alphabet, may be represented by y, or c, or x, in the secret alphabet; and so of every other letter. As there are twenty-seven characters in the telegraphic alphabet, they can, by transposition, furnish six hundred and seventy-six different kinds of secret alphabets; nearly two for every day of the year. Two persons have agreed to use, in their telegraphic correspondence, the secret alphabet. From the six hundred and seventy-six combinations, they have selected one for each day in the year, and given each their particular date. In the course of their business, it becomes necessary on the first of July, for one to transmit important information to the other. He then refers to the telegraphic book, for the alphabet belonging to that date, and from it writes his communication, as follows: The firm of G. Barlow & Co. have failed. He runs his eye along the alphabetical column for t, and finds that for the first of July it is e, that h is j, e is n, and in the same manner, he proceeds with the remaining letters of his message, which, when completed, reads as follows: Ejn stwz ys & qhwkyf p iy jhan shtknr. As every person employing the telegraph has his name, occupation and place of business registered in the record book of the office, with his telegraphic number, we will suppose, that Mr. Hammond, Builder, 57 Anson-st. Philadelphia, sends the above communication to the office for Messrs. Talford & Co. Lumber Merchants, 41 Bradford-st. New York. In the record, the former name is numbered 14; and the latter 31. The private message is then directed thus, No. 14 to No. 31, and reads thus: Mr. Hammond, &c. sends the following communication to Messrs. Talford & Co. &c. “The firm of G. Barlow & Co. have failed.” This message, in substituted characters, is copied at the receiving station, and immediately delivered. The messenger returns with the following: Syw fjhe hzyxce. To which is prefixed No. 31 to No. 14. This is sent to Mr. Hammond, who, on translating it, discovers that it must be answered by figures. He then refers to the secret numerals, under the date of the first of July, and finds the private numerals required are 897, 312, adding to it a few letters, when it reads thus, No. 14 to No. 31, 879, 312 rykkm. If it should happen, that on the 6th of December, or 13th of May, it was necessary to send a private communication, the secret alphabets of those dates are used, and so for any date of the year.

The transposed secret alphabet is not perfectly secure for private messages, when the message contains more than eight or ten words. It is, therefore, necessary to adopt some of the following modes of making it perfectly incomprehensible, and beyond the power of any person to decypher it. Any one or two, or more, of these modes may be selected and combined for this purpose. Let the following key or transposed alphabet, be used in illustrating the following rules:

1st. Let the last letter of a word remain unchanged, viz. Rome, transposed, lqde.

2d. Let the first letter of a word remain unchanged, viz. Rome, transposed, rqds.

3d. Let the first and last letter remain unchanged, viz. Rome, transposed, rqde.

4th. Let the middle letter of a word of 5, 7, 9 or 11 letters remain unchanged, viz. First, transposed, xwrfo, and in words of 4, 6, 8, 10 or 12 letters, let the two middle letters remain unchanged, viz. Rome, transposed, loms.

5th. Let the first, middle, and last letters of a word remain unchanged, viz. first, transposed, fwrft.

6th. Let the middle letter of words of 5, 7, 9, 11 or 13 letters commence the word, viz. first, transposed,lxwfo.

7th. Let the two middle letters of a word of 4, 6, 8, 10 or 12 letters commence the word, viz. Rome transposed, qdls.

8th. In a word of 4, 6, 8, 10, 12 or 14 letters, let the first half of the word be substituted for the last half, viz. Rome, transposed, dslq.

9th. Let every other entire word be reversed, viz. What is the news, transposed, ntro fw ots fns &.

10th. Let every third word be reversed.

11th. Let every fourth word be reversed.

12th. Let every fifth word be reversed.

13th. Let the three middle letters of every word of 5, 7, 9, 11 or 13 letters be reversed, viz. first, transposed, xflwo.

14th. Let every word of two or three letters be prefixed to the beginning of the following word, or affixed to the end of the preceding word, viz, State of Maine, transposed, forosqx drw&s.

15th. Let one, where double letters occur in a word, be excluded, viz. will transposed, nwv.

16th. Where two or more words, of two or three letters, follow each other, let them be joined together, viz. Cotton is on the rise, transposed, zqoq& wfq&ots lwfs.

17th. Make no separation between words of less than eight letters, viz. Cotton is on the rise, transposed, zqoq&wfq&otslwfs.

18th. Make no separation between words.

19th. Reverse the order of the letters of the whole message, viz. Cotton is on the rise, transposed and reversed, sfwl sto &q fw &qoqz.

20th. Change the key, alternately, every ten or fifteen words, using two keys.

21st. Let the two first letters of all words of four letters be affixed to the end of the preceding word, and the remaining two letters be prefixed to the word following, viz. stocks have fallen, transposed, foqzuftr gsxrvs&.

22d. Change the key irregularly, thus, for example, the first three words transpose from one key; the next three words from another key; the next three from another key, and so on.

23d. Reverse the termination of those words ending with tion, sion, ness, less, tive, ty, ly, ed, &c.

24th. Make a division of long words into two.

25th. Let those words which occur frequently and have only two or three letters remain unchanged, viz. to, a, the, of, and, for, with, &c.

26th. Let every two words, or every three, or every four, be reversed.

27th. Omit one vowel in every word.

28th. Omit the letter e at the beginning and end of a word.

29th. Omit the letter i or y at the beginning and end of a word.

30th. Omit the letter o at the beginning and end of a word.

31st. In words of 4, 6, 8, 10 or 12 letters, let the first of the two middle letters commence the word, and the last of the two middle letters end the word.

32d. Let t signify the; e for of the; f for of; u for you; wi for with; i for by; tt for that; ts for this; fr for from; n for no or not; w for will; td for to-day; tm for to-morrow; s for was; sh for shall; wd for would; sd for should; cd for could; te for to the.

We have here given a few of the various modes, by which a message can be made so complicated, that no clue will be given that shall enable the inquisitive to decypher it. Others may be easily devised, and as it is better that those using the secret alphabet should devise their own modes of transposition and reversion, none others need be given.

The following is written from the secret alphabet, and afterwards rendered more obscure by one of the methods laid down above. The key does not accompany it. Who can decypher it?

zbpvp yslup nbguxpyu zbyi, lovmy-&-yux gxp, zlegvt lovappai lubyizlvji hozovpsg zplup cbynb zbvloxbgm the jpgvizl nlep ibgm izgua zlnvlvlcu the inypvnp lhlov xmlvyloi mgua, the pnpuzvyn wmgrhzb gzhmgibpili’pv the itjcbpu the gypagvlpui and the izlveyi byxbwj wlma yu & puzyla and iovsguyux ilymulc wlci, giowkpnzl the bvegu cymicyhzpv zbgu zbloxbz zb’ yuzpurp and iowzmp. Zlal egu’i wyayux hmypi gmlux the cyop. Lmazyep yinlufopvpa, ayizgunpyi l’ pvbvlcu, and ul&g rpewmy klyui the zlvyarlup. Hgep ibgmwp byicblip ipgvnbyux eyua byixy&pu. Zlegu the slcpvzl oip the hyvp of bpg&pu, and the lmahgwmpi, cbynbyu mpxpuai voulh bgvpiyux the blvipi of the iou, sppeulc ulhgwmpi, iyunp, elvp cluavloihgv, bpjltpi the myxbzuyux zlbyi vgsya ngv; pgepibgmwp byi; and cbpuyu hozovp agji sbymlilsbj bpveluvepuz ibymgyzp zlzbip cblwlmapiz mgci, luth eigep zgwmpz cyzblov hvgulmyu’i ugep zbyup, elvip, yuwmgryux nbgvgnzpvi ibgmhmgep.

The following is from another key.

grvlvhmz agcxv hrvy all the zacyavzwe rexzgvlcekz, gvmarcyohc gradevn neelz; rmqcyogrvcl cycgcmgvn, grvclredt dmyokmova ndgrvcl blvxmzeylt, srlcaz, ovexvglt, xvncacyv, olmxml, rczgelt, all were gmkorgi ndmgcy, they zmcdvn in the adcknz, bmlmueqv the qkdoml; and they dvgbmd mgth ekgxezg. Lex grvcl zkudexv umbwa bohnvgmarvn dvmqvz hrcar xvy were to gmwvks hcgrolvmg lvzsvag, ukghrcar they were not sulxcgvnt opknov, yehvqvlt greyoi sarmyovn, ovycqz odelcozi nxmwcyo cyzvdb kynvlzgen by the xmyt; and mbgvl rmqcyo zemlvn to the vgrvlvmd lvocyzo fzacvyav in elnvl grvlv to zuciv the glqt gr in rvlrcorvzg lvglvmgz, it vxsdetz, cgsehvl in mzalgmcycyo the hmtumaw, to vrnlgr and in mslemarcyo odezvdt to us grmgi txmt zreh us the lekgv it has glmqvdvn, and the zvalvgz it has glmqvdvn, and the zvalvgz it has ncx aeqvlvn, ukg, cbzkar isye hthemdxezg kycqvlzmd gvynvyat of the rkxmy zaev yavz it was vgvl the nczgcyagcqv armlmayvlczgca of glkv zacvyavz amynczsvyzv with the svesdv as the svesdv as the svesdv nczsvyzv with them; glkvgrvedeotey the aeyglmlt, rmzyvn of the svezdvmz the svesdv rmqvv frvl zrvokmlnz grvcl lvdcocey; and grvcl lvdocey, in cgzgklx, okmlnz rvl he to grvx hrvy grvedeot dmyokczrvz, and nevzyeg zsvmwtogrvx; he to rvlhrvg the lvdcocey of the arklarvz yvodvag rvl and avmzvz to vzgvoxrvl; hvxkzg grvyzv to it. uegrey rvlmaekyg and eygrvclz, grmgzrv zsvmwz to them rvmlz them zgkncvz in lvbvlvyav to them and wvsz grvcl zarcedz esvymz eklgvxsdvz mlv.

Another example of the manner of writing secret correspondence is here given, and for those to decypher who can.

ibeg pycydc peocyenxez yndexc tcacbp bepkpaetzo pcpcgkocevd pqzpeuw bpwuaqy iatdd pctpcawu uyyc elgcvkwl tytp wlwlxgy ppe kepcuwnc ptkeb badokecy in vkqunwac wuatza qodazw prvsaue tpeoebztqg ckphvkwv epgyecp wzqv adyge zcgtey eppd wubk prozlwy pwzopwzieydt. tytp wzqv tytp qznokw ptpcawu yclep tcbbcg epdptp tytzenncyp ywzpw lccypetglydcn ezwgo eppd igwdc czgt tbzwp lhzuczpowxck, acktepzgh tvkextpc aeptveg jezpcktncw epcgh gwvcncxc cgbtpy iatdd pvgcvcw itgzcxch qkcczn zwkkepcpwgc pzuczpowxck tzckptutzo pwcytmp, eppd ypepcb zoypdt in lceppd pypvw watbc, in tpykpeptwzpkezyvw beyawkcyzwvnczac jiyzc, in geozwp dkqwy lqphyne txnled ppkeztuyytwz cucye zoypdt wodpdk ezdpwck tquucn; jeppd etquucn lcqozwtzo pwvkextpe tzntntxqegy jawzwkpgcn pvkextpc xictyj kypytzpc.

Another plan for sending secret intelligence, is, that of using select sentences, previously agreed upon by correspondents. In this plan, the first letter of each word in the sentence, combined, is made the representative of that sentence, as in the following examples:

Another arrangement, equally adapted to the same purpose as the last, is that of taking the first letter of the sentences, then arranging them in alphabetical order, and numbering them, thus:

These two systems have been found to answer in practice, and were much used in telegraphic business during the last session of Congress.

[From Silliman’s Journal.]

Art. XVI. Experiments made with one hundred pairs of Grove’s battery, passing through one hundred and sixty miles of insulated wire; in a letter from Prof. S. F. B. Morse, to the Editors, dated New York, Sept. 4th, 1843.

Dear Sirs—On the 8th of August, having completed my preparations of 160 miles of copper wire for the Electro Magnetic Telegraph, which I am constructing for the government, I invited several scientific friends to witness some experiments in verification of the law of Lenz, of the action of galvanic electricity through wires of great lengths. I put in action a cup battery of one hundred pairs, which I had constructed, based on the excellent plan of Prof. Grove, but with some modifications of my own, economising the platinum. The wire was reeled upon eighty reels, containing two miles upon each reel, so that any length, from two to one hundred and sixty miles, could be made at pleasure to constitute the circuit. My first trial of the battery was through the entire length of 160 miles, making of course a circuit of 80 miles, and the magnetism induced in my electro magnet,[10] which formed a part of the circuit, was sufficient to move with great strength, my telegraphic lever. Even forty-eight cups produced action in the lever, but not so promptly or surely.

We then commenced a series of experiments upon decomposition, at various distances. The battery alone (100 pairs) gave, in the measuring gauge in one minute, 5.20 inches of gas. When four miles of wire were interposed, the result was 1.20 inches; ten miles of wire, .57; 20 miles, .30 inches; 50 miles, .094. The results obtained from a battery of 100 pairs are projected in the following curve:

Fig. 25.

During the previous summer, I made the following experiments, upon a line of 33 miles, of number 17 copper wire, with a battery of 50 pairs. In this case, I used a small steelyard, with weights, with which I was enabled to weigh, with a good degree of accuracy, the greater magnetic forces, but not the lesser, yet sufficiently approximating the recent results to confirm the law in question.

and each successive addition of two miles, up to 33, still gave an attractive and lifting power of one-eighth of an ounce.

Curve from these Results.

Fig. 26.

A great irregularity is seen between the 10th and 12th miles, which is due, undoubtedly, to a deficiency of accuracy in the weighing apparatus. I take pleasure in sending you the following calculation of the law of the conducting power of wires, for which I am indebted to my friend Prof. Draper, of the New York City University.

On the Law of the Conducting Power of Wires.
By John W. Draper, M. D. &c. &c.

It has been objected, that if the conducting power of wires, for electricity was inversely as their length, and directly as their section, the transmission of telegraphic signals, through long wires, could not be carried into effect, and even the galvanic multiplier, which consists, essentially, of a wire making several convolutions round a needle, could have no existence. This last objection was first brought forward by Prof. Ritchie, of the University of London, as an absolute proof, that the law referred to is incorrect. There is, however, an exceedingly simple method of proving that signals may be despatched through very long wires, and that the galvanic multiplier, so far from controverting the law in question, depends for its very existence upon it.

Assuming the truth of the law of Lenz, the quantities of electricity which can be urged by a constant electromotoric source through a series of wires, the lengths of which constitute an arithmetical ratio, will always be in a geometrical ratio. Now the curve whose ordinates and abscissas bear this relation to each other, is the logarithmic curve whose equation is aʸ = x.

1st. If we suppose the base of the system, which the curve under discussion represents, be greater than unity, the values of y taken between x = 0, and x = 1, must be all negative.

2d. By taking y = 0, we find that the curve will intersect the axis of the x’s, at a distance from the origin, equal to unity.

3d. By making x = 0, we find y to be infinite and negative. Now, these are the properties of the logarithmic curve, which furnish an explanation of the case in hand. Assuming that the x’s represent the quantities of electricity, and the y’s the lengths of the wires, we perceive at once, that those parts of the curve which we have to consider, lie wholly in the fourth quadrant, where the abscissas are positive and the ordinates negative. When, therefore, the battery current passes without the intervention of any obstructing wire, its value is equal to unity. But, as successive lengths of wire are continually added, the quantities of electricity passing, undergo a diminution, at first rapid, and then more and more slow. And it is not until the wire becomes infinitely long that it ceases to conduct at all; for the ordinate y, when x = 0, is an asymptote to the curve. In point of practice, therefore, when a certain limit is reached, the diminution of the intensity of the forces becomes very small, whilst the increase in the lengths of the wire is vastly great. It is, therefore, possible to conceive a wire to be a million times as long as another, and yet, the two shall transmit quantities of electricity not perceptibly different, when measured by a delicate galvanometer. But, under these circumstances, if the long wire be coiled, so as to act as a multiplier, its influence on the needle will be inexpressibly greater than the one so much shorter than it. Further, from this we gather that for telegraphic despatches, with a battery of given electromotoric power, when a certain distance is reached, the diminution of effect for an increased distance becomes inappreciable.

THE GALVANOMETER
OR GALVANOSCOPE.

This useful instrument, the invention of which is based upon Oersted’s discovery of the deflection of the magnetic needle, by the action of conducting wires conveying galvanic currents, seems to have furnished to most of the inventors of telegraphs, the main spring of communication. It was a very natural suggestion, as being the most convenient and ready mode of obtaining the required motion, by making and breaking the galvanic circuit. Thus Steinheil, Wheatstone and Bain have availed themselves of this one idea to effect that part of the telegraphic operation which may be called the galvanic, in contradistinction to the mechanical parts, which last have varied considerably with different operators. The construction and operation of the galvanometer may be understood by reference to the figures [27], [28], [29]. A A, [fig. 28], are two long coils of covered copper wire, a side view of which is shown in [fig. 27]. These coils are connected with the binding screws, L L, attached to the frame, or box, holding the coils.Two coils are used for the convenience of allowing the pivot sustaining the magnetic needle to pass between them; one coil might be used, by leaving room enough between the wires for a socket for the pivot, but the arrangement, represented, is the most readily constructed. A side view of the instrument, [figure 27], shows the arrangement of the needles, two of them being generally used to increase the operation of deflection, and to neutralize the influence of the earth’s magnetism. The pair of needles is usually denominated, an astatic needle, or a needle without directive power; as the current traversing a conducting wire gives different directions to needles placed above and below the wire, the action upon the two needles thus placed is combined, by arranging their poles in opposite directions. When the current is in the direction indicated by the arrows in [figure 27], the north pole of the needle, within the coil, is carried in a direction from you, as you face the drawing, and the north pole, without the coil, in a contrary direction. The operation upon the south pole is the reverse. Changing the direction of the galvanic current, reverses the motions. It is usual to apply the force of torsion, or of a hair spring, or of the superior weight of one extremity of the needle, to act against the deflective force of the current, and to attach a graduated scale to the instrument, fixing it between the uppermost needle and the coils as in [figure 29]. Instead of deflecting the needle, the coils themselves may be deflected, as in the galvanoscope of Prof. Page, invented in January, 1837, and described by him in the 33d vol. of Silliman’s Journal, page 376. The object of this contrivance was to enable him to use powerful magnets and lighter coils. This modification of the galvanoscope, Mr. Bain has preferred as the means of operating his telegraph.

Fig. 27.

Fig. 28.

Fig. 29.

An Interesting Experiment of Supporting a Large Bar of Iron within the Helix.
Discovered by Mr. Vail, January, 1844.

It has been shown, many years since, that a magnetic needle would be drawn into and suspended within a helix, conveying a galvanic current, and that in the case of using large bar magnets, the coils or helices might be made to move over them, as in De La Rives’s rings; but in no instance, I believe, has it been recorded, or observed, that a bar of iron weighing a pound or more, could be drawn up into the helix and there sustained in the air, as it were, without support. If the helix, as shown in [figure 30], be connected with from 6 to 12 pairs of Grove’s battery, the bar may be drawn up into its centre and there sustained in a vertical position by the action of the helix, forming an exceedingly interesting and paradoxical experiment.