Fig. 51.
Fig. 51.
Figure 51represents a side view of the apparatus, used at thereceivingstation:a, ais a side view of the multiplier, composed of 30,000 feet of wire, (almost 5½ miles,) upon a table, B:n, sis the magnetic bar, weighing 30 pounds, from which rises a vertical stem,o, upon which is a rod at right angles, supporting a mirror, H, on one end, and at the other a metallic ball, I, as a counteracting weight to that of the mirror. The magnetic bar is suspended by a small wire, fastened to the vertical stem, and at the top is wound round the spiral of the screw,i, which turns in the standards,h′andh, upon the platform, A, and which is secured to the ceiling. In the standards,h′, there is cut a female screw, of the same gradation as that upon which the wire is wound. By this means, the magnetic bar may be raised or let down, by turning the screw, without taking the bar from its central position in the multiplier:gis a screw for fastening the spiral shaft, when properly adjusted. P and N are the two ends of the wire of the multiplier. G is a stand for supporting the spy-glass, D, and also the case, E, into which slides the scale, F. The mirror, H, is at right angles with the magnetic bar, and presents its face to the spy-glass, D, as also to the scale at E. It is so adjusted, that the reflection of the scale at E, from the mirror, may be distinctly seen by the spy-glass. If the magnetic bar turns either to the right or left, the mirror must move with it, and if a person is observing it through the spy-glass, the scale will appear to move at the same time, thereby presenting to the eye of the observer another part of the scale than that seen when the bar is not deflected. The figures on the scale will show in what direction the bar has turned, and thus render it distinct to the observer, the only apparent object of the mirror, spy-glass and scale.
For the purpose of generating the galvanic fluid, they use the magnetoelectric machine. Their plan, being unwieldy and difficult to operate, is omitted, and in its stead, we introduce that form of it, invented by Dr. Page, which has already been described in figures45,46and47. There is also required for the purpose of making the desired deflections of the magnetic bar, a commutator, or pole changer, such as we have described in figures48,49and50.Figure 51represents that portion of the apparatus at thereceivingstation. The magneto electric machine, and the pole changer, properly connected, are the instruments of thetransmittingstation. Two wires, or one wire and the ground, form the circuit between these two stations. The machine is put in operation by turning the crank, and the person sending the intelligence is stationed at the commutator, and directs the current through the extended wires to the multiplier of the receiving station, so as to deflect the bar to the right or left, in any succession he may choose, or suspend its action for any length of time.
“But in the apparatus for observation, the observer looks into the spy-glass, and writes up the kind and results of the variations of the magnetic needle. In order to have a control of the recorder, let there be a good number of spy-glasses directed towards the same mirror, in which observers may watch independently of each other. Suppose that five variations of the magnetic needle signifies a letter. L denotes a variation to the left, and R to the right. Then, might r r r r r denote A; r r r r l denote B; r r r l r denote C; r r l r r denote D; and so on. In the whole, we obtain, by the different arrangements of the five, which are made with the two letters, R and L, 32 different telegraphic signs, which may answer for letters and numbers, and of which we can select those where the most changes are introduced betweenrandl, as the most common letters, in order, in the best possible manner, to notice the constant variations of the magnetic needle.”
The following would be the alphabetical signs, as arranged from the above directions:
It will be seen, that, by representing the letters and numerals with these variously combined deflections of the needle, words and sentences may be transmitted. At the end of each letter there is a suspension of the action of the bar for a short time, and at the end of a word, a still longer pause. This plan of an electric telegraph was tried for a distance of one mile and a quarter, in Göttingen. Of its further success, we are not informed.
“Messrs. Taquin and Ettieyhausen made experiments with a telegraphic line over two streets in Vienna, 1836. The wires passed through the air and under the ground of the Botanic garden.”
No other account appears to have been given of their experiments than that quoted above.
Soon after my connection with Professor Morse as copartner, and at the time I was constructing an instrument for exhibiting the advantages of his telegraph to a committee of Congress, it occurred to me, that a plan might be devised, by means of which the letters of the alphabet could be employed in recording telegraphic messages. I immediately gave it my attention, and produced the following plan:
Figure 52represents a front and side view of the instrument.
Figure 55is a top view.
Figure 56is a back view.
The same parts are represented by the same letters in the three views. Infigure 52, Q, Q is the platform upon which the whole instrument is placed. M and M are wooden blocks supporting parts of the instrument, K is the helix of the soft iron bar, H, passing through its centre, and there is another coil and bar directly behind this; the two making the electro magnet. G is its armature, fastened to the lever, F, F, which has its axis at I, (seen infigure 55, at X, X.) R is a brass standard for supporting the lever, F, upon its axis, by means of two pivot screws:aandaare two screws passing vertically, through the standard, R, for limiting the motion of the lever, F, F. J is a spiral spring, at its upper end, fastened to the lever, F, and at its lowerend passes through the screw, L, by which it is adjusted, so as to withdraw the armature from the magnet, after it has ceased to attract, and for other purposes, hereafter to be explained. N and O is a brass frame, containing the type wheel, B′, and the pulley, E and U. P and P represent the edge of a narrow strip of paper, passing between the type wheel and pulley, E. D is the printer, which, at the bottom, forms a joint with the end of the lever F andr. B represents twenty-four metallic pins, or springs, projecting at right angles from the side of the type wheel; each pin corresponding in its distance from the centre of the type wheel, to its respective hole, represented by dots upon, the index, C; so that if the pin is put in any one of the holes, the type wheel, in its revolution, will bring its corresponding pin in contact with it.
Fig. 52.
Fig. 52.
There are 24 holes corresponding to the following letters of thealphabet. A, B, C, D, E, F, G, H, I, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, and the types are lettered accordingly. The cog wheels, T and S, are a part of the train of the clock. The lever, F, F, has two motions, one up and another down, and both are employed by an attachment at the end of the lever,r, and in the following manner: figures53 and 54represent a front and end view of the roller, E, and printer, D, (figure 52,) enlarged. D is the printer,figure 53, of the form shown by D, (figure 54.) E is the roller over which the paper, P, is carried. A is the front of the type having ears,h, h, projecting from each side. Through the sides of the printer, D, D, a rod, U, passes, in order to give more firmness to the frame. The rod projects a little on each side of the frame at J, J. These projections slide in a long groove in the frames, N and O,figure 52, by which the printer is kept in its position, and allowed freely to move up and down. It will be observed that the upper parts of the frame, D, D, extends over the top of the roller, E, and nearly touch each other, but are so far separated, as to let the type, A, of the type wheel, in its revolution, freely pass between them:d′, d′, are the sides of the joint, which are connected with the lever, F,fig. 52. From the construction of this part, it will appear that if the printer, D, is brought down by the action of the magnet upon the lever, the two projections,k, k, will come in contact with the ears,h, h, and bring the type in contact with the paper upon the roller, E, and produce an impression. Infigure 54is shown a ratchet wheel,i, on the end of the roller, E, a catch,e, and spring,c′, adapted to the ratchet. Upon the release of the lever, F,fig. 52, the spring, J, will carry down the lever on that side of its axis, and up atr, which will cause the roller, E, to turn, and consequently the paper, P, to advance so much by the action of the catch,e, upon the ratchet wheel, as will be sufficient for printing the next letter.
Fig. 53.Fig. 54.
Fig. 53.Fig. 54.
Figure 55represents a top view of the machine. S is the barrel upon which is wound a cord, sustaining a weight which drives the clock train,and upon the same shaft with it is a cog wheel driving the pinion,m, on the shaft, T; and on the same shaft, T, is another cog wheel, driving the pinion,n, of the type wheel shaft, I′. K and K, are the helices of the large magnet, of which H and H are the soft iron arms. M, M, M, M, are the blocks which support the instrument. F and F is the lever,aandaits adjusting screws;x′andx′its axis;kandkare the two upper coils of the two electro magnets at the back part of the instrument for purposes hereafter to be described;xis the wire soldered to the plate buried in the ground;pis the wire proceeding to the battery;cis the connecting wire of the two electro magnets,kandk; w is the support of the pendulum;vis the escapement wheel; A is the type wheel; D and D is the printer, and B the roller over which the paper, P, is carried.
Fig. 55.
Fig. 55.
Fig. 56.
Fig. 56.
Figure 56represents a back view of the instrument;k,kandk,kare the coils of two electro magnets, surrounding the soft iron bars,d,dandd, d;bandbare the flat bars through whichd, dandd, dpass, and are fastened together by the screw nutsc, candc, c. The right hand electro magnet is fastened to the blocks, M and M, by the support,fandf; from which proceeds a bolt passing between the coils,kandk, and the block,h, with a thumb-nut upon it, by which the whole is permanently secured. In the same manner the left hand magnet is secured to the block, M. R′ is the outside portion of the brass frame containing the clock work. W is a standard fastened to R′, for supporting the pendulum, Y. X, Y, andlare parts common to a chronometer for measuring the time, viz. the escapement and pendulum. The escapement wheel has 24 teeth, corresponding in number with the type on the wheel, and such is the arrangement of the parts, that when the pendulum is upon the point ofreturn, either on the right or left hand, a type is directly over the paper, and the armature,g, is near the face of one or the other of the magnets; so that, if an impression is to be made with the type, thus brought to the paper, the pendulum, Y, is ready to be held by the magnet at the same time from making another swing until the type has performed its office, which will be hereafter explained.
A shows the type as they are arranged on the wheel. The types are square, and move freely in a groove, cut out of the brass type wheel. At 1 and 2 are seen flat brass rings, which are screwed to the wheel, and over the types, confining them to their proper places. Z is a spiral spring, of which there is one to each type, by means of which the type is brought back to its former position, after it is released by the printer. Through each type there is a pin, against which the inner end of the spiral spring rests. The outer end of the spring rests against the circular plate. W represents the wire from the upper helix, soldered to the metallic frame, R′. The two helices of the left hand magnet are joined together, and from the bottom helix the wire proceeds to the lower coil of the right hand magnet. These two helices are likewise connected, and the wire leaves the upper coil atx. Thus the wire is continuous fromwtox. Fromx, the wire is continued to a copper plate, buried in the earth. The frame, R′, being brass, the arbor of the type wheel, and the wheel itself, and each being in metallic contact, they answer as a continuous conductor with the wire,w, for the galvanic fluid.
The index,c,figure 52, is insulated from the frame, N, being made of ivory. There is inserted in the ivory, a metal plate, containing the holes, to which is soldered a wire,q, connected with the back coil, K. The two helices being connected, the wire of the front helix comes off atp, and from thence is connected with one pole of the battery; from the other pole, it is extended to the distant station, and is there connected with a similar instrument. It will be observed, that the circuit is continuous, except between the type wheel and the metal plate in the ivory. When neither station is at work, the batteries of both are thrown out, and their circuits, retaining in them the magnets of both stations, are closed. For this purpose, there is an instrument at each station, resembling in some respects the pole changer, figures48,49and50. If one of the stations wish to transmit by reversing his circuit instruments, the battery is instantly brought into the circuit. Through the agency of the clock work and weight, and the pendulum, both instruments are vibrating together, and their type wheels are so adjusted, that whenA type, of one station, is vertical, theA type, of the other station, is also vertical. Now, suppose one station wishes to transmit to the other, the wordBoston, for example: hefirst brings his battery in the circuit, then places a metallic pin in the hole of his index, C, marked for the letter B. When the type wheel shall have brought round the pin, corresponding to the type, B, on the wheel, its pin will come in contact with the inserted pin of the index, and instantly the circuit is established. The fluid, passing through the coils of the magnets, on each side of the pendulum, will hold it, and also passing through the coils, K, will bring down the lever, F, F, and with it, the printer, D, which, as heretofore described, in figures53 and 54, will bring the type, with considerable force, against the paper. The instant the two pins have come in contact with the moving pin, it is taken out and put in the hole, O, when the same operation is performed, and in like manner for the remaining letters of the word. The pin can be so arranged, as to be thrown out the instant a complete contact is made.
The rapidity of this printing process would be as follows: Suppose the pendulum makes two vibrations in a second; that is, it goes from right to left in half a second, and returns in half a second. Since, then, a single letter is brought to thevertical position, ready to be used if needed, at the end of each vibration, it is clear, that two letters are brought to the vertical position every second, or 120, every minute. This is not, however, the actual rate of printing; for, in the wordBoston, the type wheel, after B is printed upon the paper, must make so much of a revolution as will bring the letter O to the paper. This will require 12 vibrations of the pendulum; S will require 4; T, 1; O, 18, and N, 22; equal to 57, to which add 6, the time required to print each letter, will make it 63. This, divided by 2, gives 31½ seconds, the time necessary to print 6 letters. If we now take an ordinary sentence, and estimate, in the same manner, the time required to print it at the distant station, we shall be able to find what number of letters it can print per minute.
“There will be a declaration of war in a few days, by this government, against the United States. Orders have just been received to have all the public archives removed to Jalapa, which is sixty miles in the interior, for safe keeping.”
Here are 184 letters, and would require 2266 vibrations, to which add 184, the number of letters would give 2450 half seconds, equal to 1225 seconds, the time required for printing the message; or over 20 minutes; the rate being six and two-thirds seconds for each letter.
If, however, a vocabulary is used, with the words numbered, and instead of using the 26 letters of the alphabet on the type wheel, we substitute the 10 numerals, in their place, we reduce the time required for a revolution of the wheel, and it is clear that this same message may be transmitted in much less time.
The following numbers represent the words of the same message, in the numbered vocabulary: 48687, 54717, 4165, 1, 12185, 34162, 54078, 25393, 1, 18952, 11934, 6177, 48766, 21950, 1106, 48652, 51779, 46532, 34475, 22991, 28536, 4321, 40254, 49085, 22991, 1391, 48652, 39087, 3845, 41278, 49085, 28536, 54536, 28668, 45008, 31634, 25393, 48652, 27326, 19865, 42813, 28592. Here are 42 numbers, and 196 figures. To 196 add 42, the spaces required, and we have 238 impressions to make, to write the sentence thus represented. By calculation, we find there is required, in order to bring each numeral and space in its proper succession, to the vertical position, 1624 vibrations of the pendulum, which, at the rate of two to the second, gives the time required to transmit the message at 812 seconds, or nearly 13 minutes, being at the rate of 18⅓ letters per minute.[29]
If, however, the vibrations of the pendulum are increased at the rate of 4 in a second, then the time required for the transmission of the message would be almost 7 minutes, and at the rate of 36⅔ letters per minute.[30]If it be increased to 6 vibrations per second, then the time would be 4½ minutes, and at the rate of 55 impressions per minute.
The modes of using the English letter for recording telegraphic messages are various, and they may be classed, as, First, Those which are rapid in transmission; expensive in construction, and complicated in machinery. Second, The less rapid in transmission; economical in construction, and simple in its machinery. Third, The slow in transmission; less expensive than the first class in construction; but complicated in its machinery.
To thefirstclass, belong those using 26 types; one for each of the letters of the alphabet, and 13 extended wires, from station to station, with more or less battery. These types are arranged in a row, directly over the paper which receives the impression, and consequently require a strip of paper some 4 or 5 inches broad. Each type is furnished with an electro magnet and lever, answering as a hammer to bring down the types upon the paper. As the types are arranged in a straight line, they would present the following order:
Here we have the style of this kind of printing. By spelling the letters on the first line, then on the second, and so on, the words “Printing Telegraph” can be made out. Those letters which follow each other in the word, and also follow each other in the alphabet, are placed upon the same line, but when a letter occurs preceding the last, a new line must be taken, otherwise the word cannot be read. It will appear, that in this mode, sometimes two or three, or four letters, may be printed at one and the same instant, where they succeed each other in alphabetical order. This plan is extremely rapid forone instrument, but extremely slow forthirteen wires.
Supposing two such instruments are used upon a line of 40 miles, and suppose the wire to cost per mile, fifty dollars. The expense for wire alone would be $26,000. There are other expenses which we will omit in this, as well as those plans which will be described hereafter. Let it be assumed, in order to make equal comparison throughout, that the number of successive motions of the type lever, in these various plans about to be given, are 4 to a second. But as this instrument may make, with two or more of its levers, two or more impressions per minute, let it be 8 instead of 4 per second. It will then be capable of transmitting 480 letters per minute. With all this, there are many disadvantages, which will be developed as we proceed.
Under the same class, there is another plan, using the 26 types upon the ends of as many levers, each lever employing the electro magnet, and the line consisting of 13 wires. In this arrangement the types are made to strike in any succession required by the message, at thesame pointupon the paper,falling backand resuming their first position, after having printed their letter, in order to allow the next type to occupy the same point previously occupied by the other. The printing of this plan will appear on paper as ordinary printing. Thus,Printing Telegraph. If we suppose that 4 hammers, carrying type, can strike thesame pointin a second, and each resumetheir original position in succession, thus passing each other without collision, it may print at the rate of 240 letters per minute.[31]The instrument would be a complicated one and subject to derangement.
To thesecondclass, belong all those which print in letters of an hieroglyphical character. Thefirstplan is that employing one wire and one motion. Under this head, is that of Prof. Morse’s. He employs but one wire and one electro magnet for printing, which has but one motion. Suppose this to be capable of operating with the same speed as the preceding, viz. four motions per second. The telegraphic alphabet as adopted by Prof. Morse require for each letter the following number of motions of the type or pen lever, as lines require time in proportion to their length, they are so estimated: A 3, B 5, C 4, D 4, E 1, F 4, G 5, H 4, I 2, J 6, K 5, L 5, M 4, N 3, O 3, P 5, Q 5, R 4, S 3, T 2, U 4, V 5, W 5, X 5, Y 5, Z 5.
If we take thestandard numberof types for each letter constituting it printer’s case, considering Z as 2, we shall have A 85, B 16, C 30, D 44, E 120, F 25, G 17, H 64, I 80, J 4, K 8, L 40, M 30, N 80, O 80, P 17, Q 5, R 62, S 80, T 90, U 34, V 12, W 20, X 4, Y 20, Z 2. The whole number of letters are 1177. The number of motions required to transmit them would be 3420, to which add, one motion for the time required to space a single letter, and we have 4597 motions, made in printing 1177 letters which will make the average number of motions to each letter 3¹⁰⁶⁶⁄₁₁₇₇, nearly 4. Let it be 60 per minute. Expense for one wire of 40 miles, $2000.
Second plan, is that where two wires are used, two magnets, two type levers, and the telegraphic characters, such as are represented in table 1, page 30. The first three letters require three motions each; the next 16, require 2 each, and the last 7, require 3 each. Taking the 1177 letters, the motions required to transmit them in the characters of this alphabet, would be, 2195 + 1177 for spaces and would equal 3372, which divided by 1177, would give the average number of motions at 2¹⁰¹⁸⁄₁₁₇₇ for each letter, nearly three or 80 per minute. Cost of wire $4000.
Third plan, is that using three wires, three magnets, three type levers and the telegraphic characters represented in table second, page 30. The seven first would require one motion each, and the remainder two each. Taking 1177 letters, the motions required to transmit them, would be 1917 + 1177 for spaces, and would equal 3094 motions, which, divided by 1177, would give the average number of motions 2⁷⁴⁰⁄₁₁₇₇ for each letter, nearly 2⅔, or 85 letters per minute. Cost of wire $6000.
Fourth planconsists in using four wires, four electro magnets, four type levers, and the telegraphic characters of the third table. Thefirst sixteen letters require the time of but one motion each; the remainder, two each. Using 1177 letters, the motions required to transmit them would be 1506 + 1177 for spaces, and would equal 2683, which divided by 1177, would give the average number of motions 2³²⁹⁄₁₁₇₇ for each letter, nearly 2⅓, or 103 letters per minute. Cost of wire $8000.
Fifth plan, is that of using five wires, five electro magnets, five type levers, and the telegraphic characters of the 4th table. The characters would require one motion each, equal to 1177 + 1177 for spaces, and would equal 2354, which, divided by 1177, would give the average number of motions, 2 for each letter, or 120 letters per minute. Cost of wire $10,000.
We now come to thethirdclass, in which 26 types are used, arranged upon the periphery of a wheel, in alphabetical order, and require to be brought to one certain point, where the paper is ready to receive the impression of the type, by another arrangement, distinct from the type wheel and its machinery. Of this plan, is that which has been already described in figures52,55and56. The estimate is there carried out, at 4 motions per second, gives 36⅔ letters per minute. Cost of wire $2000.
The following table will show the comparative value of these various methods:
We find by comparison that Morse’s plan, No. 3, of using a single wire, with a single instrument, produces 60 characters per minute; while No. 1, with 13 wires, and one instrument, produces 480 characters per minute. Let, however, the 13 wires be multiplied by 60, (the number of characters which a single instrument of the plan, No. 3, can transmit,) the number of characters which 13 wires, with 13 instruments would then produce, are 780 or 300 more than thesingle instrument, with 13wires. The same comparisons may be made with the other plans, and it will be found that no advantage can be gained by their adoption.
All electro magnetic telegraphs require as their basis, the adoption of theelectro magnet, where recording the intelligence is an object, and it would seem, must be applied in a manner equivalent to that mode adopted by Prof. Morse; that is, the application of the armature to alever, and its single movement produced by closing and breaking the circuit. It is, therefore, safe to assume, that whatever improvement in one plan may be made to increase the rapidity of the movements of those parts of the telegraph which belong to the electro magnet, are equally applicable to any other plan, provided too much complication, already existing, does not counteract and defeat the improvement.
Some plans, however, use an extra agent besides the electro magnet, which is employed for measuring the time of the revolution of the type wheel, and the electro magnet is only called in, occasionally, to make the impression. In such plans the rapidity of communication demands the combined action, alternately, of both magnets. This, of course, increases the complication, and must certainly be considered a departure from other more simple arrangements. Whatever will reduce the inertia of mechanical movements and bring them to act with an approximate velocity, at least of the fluid itself, will increase the rapidity of transmission. The more the instrument is encumbered with the sluggish movements of material bodies, the less rapid, inevitably, must be its operation, even where several co-operating agents are assisting, in their respective spheres, to increase the rapidity of the motion. Such is the case with the several kinds of letter printing telegraphs: very weighty bodies, comparatively speaking, are set in motion, stopped, again set in motion, and along with this irregular motion, other parts perform their functions. There must be a courtesy observed among themselves, or matters do not move on as harmoniously as could be desired. This is not always the case, especially where time is the great question at issue.
All printing telegraphs which use type, arranged upon the periphery of a wheel, must have, of necessity, these several movements, viz. the irregular revolution of the type wheel, stopping and starting at every division or letter; the movement of the machinery, called the printer; the irregular movement of the paper, at intervals, to accommodate itself to the letter to be printed; the movement of the inking apparatus, or what is not an improvement in cleanliness, paper of the character used by the manifold letter writer. So many moving parts, are so many impeding causes to increased rapidity, and are, to all intents and purposes, acomplication.
The requirements of a perfect instrument are: economy of construction, simplicity of arrangement, and mechanical movements, and rapidity of transmission. To use one wire is to reduce it to the lowest, possible economy. If there is but one movement, and that has all the advantages which accuracy of construction, simplicity of arrangement and lightness, can bestow upon it, we might justly infer that it appeared reduced to its simplest form.
The instrument employed by Professor Morse has but a single movement, and that motion of a vibratory character; is light and susceptible of the most delicate structure, by which rapidity is insured; the paper is continuous in its movement, and requires no aid from the magnet to carry it.
The only object that can be obtained by using the English letters, instead of the telegraphic letters, is, that the one is in common use, the other is not. The one is as easily read as the other, the advantage then is fanciful and is only to be indulged in at the expense of time, and complication of machinery, increasing the expense, and producing their inevitable accompaniments, liability of derangement, care of attendance, and loss of time.
The following description is taken from a pamphlet, published by T. S. Hodson, 15 Cross street, Hallon Garden, London, 1839, for the proprietors. It is unnecessary to copy the legal and technical wordy mass of the specification, embracing fifty-nine pages of closely printed matter of octavo size. A full description will be given, with the accompanying figures, so as to enable the reader fully to comprehend Mr. Wheatstone’s plan.
His arrangement requires the service of five galvanometers, in every respect similarly constructed as that described by the figures27,28and29.Figure 57is a representation of his dial, which is also a covering to the case containing, in the interior, the five galvanometers and their wires, (shown at the opening in the dial board,) and numbered, 1, 1; 2, 2; 3, 3; 4, 4, and 5, 5. The coils of the multipliers are secured with their needles to the case, having each exterior needle projecting beyond the dial, so as to be exposed to view. Of the wires from the coils, five are represented as passing out of the side of the case, on the left hand, and are numbered 1, 2, 3, 4 and 5. The other five wires pass out on the right hand, and are numbered in the same manner. The wires of the same number as the galvanometer, are those which belong to it, and are continuous. Thus the wire 1, on the left hand, proceeds to the first coil of galvanometer 1, then to the second coil, and then coming off, passes out of the case, and is numbered 1, on the right hand. So of the other wires, thus numbered. The dial has permanently marked upon it, at proper distances and angles, twenty of the letters of the alphabet, viz. A, B, D, E, F, G, H, I, K, L, M, N, O, P, R, S, T, V, W, Y. On the margin of the lower half of the dial are marked the numerals, 1, 2, 3, 4, 5, 6, 7, 8, 9 and 0. The letters C, J, Q, U, X, Z, are not represented onthe dial, unless some six of those already there are made to sustain two characters each, of which the specification is silent. Each needle has two motions; one to the right, and the other to the left. For the designation of any of theletters, the deflection of two needles are required, but for thenumerals, one needle only. The letter intended to be noted by the observer, is designated, in the operation of the telegraph, by thejoint deflectionof two needles, pointing by their convergence to the letter. For example, the needles, 1 and 4, cut each other, by the lines of their joint deflection, at the letter V, on the dial, which is the letter intended to be observed at the receiving station. In the same manner any other letter upon the dial may be selected for observation. Suppose the first needle to be vertical, as the needles 2, 3 and 5, then needle 4 being only deflected, points to the numeral 4, as the number designed.