SAMUEL F. B. MORSE, ESQ.

A subsequent letter from Captain Pell, dated February 1st, 1838, after

having seen the operation of the telegraph at the University, has the

following paragraph:

“When, a few days since, I examined your instrument, _I recognized in

it the principles and mechanical arrangements_, which, on board, I had

heard you so _frequently explain_ through all their developments.”

From a letter now in possession of the author, and addressed to him by

Prof. Morse, we make the following extract:

“In 1826, the lectures, before the New York Atheneum, of Dr. J. F.

Dana, who was my particular friend, gave to me the first knowledge

ever possessed of electro magnetism; and some of the properties of

the _electro magnet_; a knowledge which I made available in 1832 as

the basis of my own plan of an electro telegraph. I claim to be the

original suggestor and inventor of the electric magnetic telegraph,

on the 19th of October, 1832, on board the packet ship Sully, on my

voyage from France to the United States, and, _consequently_, the

inventor of the first, really _practicable telegraph on the electric

principle_. The plan then conceived and drawn out in all its essential

characteristics, is the one now in successful operation. All the

telegraphs in Europe, which are practicable, are based on a different

principle, and, _without an exception_, were invented subsequently to

mine.

“The thought occurred to me, in a general conversation, as seated at

the table with the passengers, in which the experiments of Franklin

to ascertain the velocity of electricity through three or four miles.

The thought at once occurred to me that electricity might be made the

means of conveying intelligence, and that a system of signs might

easily be devised for the purpose. I ought, perhaps, to say, that the

conception of the idea of an _electric telegraph_, was original with

me at that time, and I supposed that I was the first that had ever

associated the two words together, nor was it until my invention was

completed, and had been successfully operated through ten miles, that

I, for the first time, learned, that the idea of an electric telegraph

had been conceived by another. To me it was original, and its total

dissimilarity from all the inventions and even suggestions of others,

may be thus accounted for. I had not the remotest hint from others,

till my whole invention was in successful operation. I employed myself

in the wakeful hours of the night, as well as in the tedious hours of

the day, _in devising the signs, adapting them to a single circuit of

wire_, and in _constructing machinery which should record the signs

upon paper_, for I thought of no plan short of a mode of recording.”

On the second of September, 1837, the author, with several others,

witnessed the first exhibition of this electric telegraph, and soon

after became a partner with the inventor. Immediate steps were taken

for constructing an instrument for the purpose of exhibiting its powers

before the members of Congress. This was done at the Speedwell Iron

Works, Morristown, N.J. and exhibited in operation with a circuit of

two miles. A few days after, it was again exhibited at the University

of the City of New York, for several days, to a large number of invited

ladies and gentlemen. The circuit at this time was increased to ten

miles. Immediately after this exhibition the instruments and ten

miles of wire were taken to Washington, and continued in operation

for several months, in the room of the Committee on Commerce at the

capitol. Its history and progress, after this period, may be gathered

from the preceding documents, printed by order of Congress.

_Schilling Electric Telegraph._

We make the following extract in relation to Schilling’s telegraph from

the Polytechnic Central Journal, Nos. 31, 32, 1838:

“Baron Schilling, of Caunstadt, a Russian Counsellor of State, likewise

occupied himself with telegraphs by electricity, (see Allgem Bauztg,

1837, No. 52, p. 440,) and had the merit of having presented a much

simpler contrivance, and of removing some of the difficulties of the

earlier plans. He reckoned many variations to the right, or left,

following in a certain order for a telegraphic sign, as, indeed, in

this manner, the needle was strongly varied, and only came to rest

gradually, after many repeated vibrations; he introduced a small rod

of platinum, with a scoop, which dipped into a vessel of quicksilver,

placed beneath the needle, and by the check given, changed the

vibration of the needle into sudden jerks. In order to apprise the

attendant of a telegraphic despatch, he loosed an alarm. How much of

this contrivance was Schilling’s own, or whether a portion of it was

not an imitation of Gauss and Weber, the author cannot decide, but that

Schilling had already experimented, probably with a more imperfect

apparatus, before the Emperor Alexander, and still later before Emperor

Nicholas, is affirmed by the documents quoted.”

From the report of the “Academy of Industry,” Paris, February, 1839, we

make the following extract, in relation to the same subject:

“At the end of the year, 1832, and in the beginning of 1833, M.

Le Baron de Schilling constructed, at St. Petersburg, an electric

telegraph, which consisted in a certain number of platinum wires,

insulated and united in a cord of silk, which put in action, by the aid

of a species of key, 36 magnetic needles, each of which were placed

vertically in the centre of a multiplier. M. de Schilling was the first

who adapted to this kind of apparatus, an ingenious mechanism, suitable

for sounding an alarm, which, when the needle turned at the beginning

of the correspondence, was set in play by the fall of a little ball of

lead, which the magnetic needle caused to fall. This telegraph of M. de

Schilling, was received with approbation by the Emperor, who desired it

established on a larger scale, but the death of the inventor postponed

the enterprise indefinitely.”

Dr. Steinheil in his article “upon telegraphic communication,”

published in the London Annals of Electricity, states, “that the

experiments instituted by Schilling, by the deflection of a single

needle, seems much better contrived, than the arrangement which Davy

has proposed, in which illuminated letters are shown by the removal of

screens placed in front of them.”

It would appear, that the French report is either incorrect, or that

M. de Schilling had two plans in contemplation. His plan as intimated

in the first and third extracts, is that of using a single needle in

the form of a galvanometer, by means of which he made his signals, for

instance, one deflection to the right might denote _e_; two _i_; three

_b_: one deflection to the left _t_; two _s_; three _v_. His code of

signals would then be devised in this manner:

rl A rrrl K llr U

rrr B lrrr L lll V

rll C lrl M rlrl W

rrl D lr N lrlr X

r E rlr O rllr Y

rrrr F llrr P rlrr Z

llll G lllr Q rrlr &

rlll H lrr R lrrl go on

rr I ll S lrll stop

rrll J l T llrl finish

rlrlr 1 lrlrl 6

rrlrr 2 rrllr 7

rlllr 3 rllrr 8

lrrrl 4 llrll 9

lrrll 5 llrrl 0

If, however, his plan was that ascribed to him, by the Academy of

Industry, of using 36 needles and 72 wires, it was exceedingly

complicated and expensive, and was similar to that invented by Mr.

Alexander, with the exception that Schilling used twice the number of

wires.

[27]_The Electro Magnetic Telegraph, of Counsellor Gauss and Professor

William Weber, invented at Göttingen, 1833._

The deflection of the magnetic bar, by means of the multiplier, through

the agency of the galvanic fluid, excited by the magneto electric

machine, is the basis of their plan.

[27] From the Polytechnic Central Journal, 1838, Nos. 31, 32.

[Illustration: FIG. 51.]

Figure 51 represents a side view of the apparatus, used at the

_receiving_ station: _a, a_ is a side view of the multiplier, composed

of 30,000 feet of wire, (almost 5½ miles,) upon a table, B: _n, s_ is

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′_ and _h_, 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: _g_ is 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 magneto

electric 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 figures 45, 46 and

47. 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 figures 48, 49 and 50. Figure 51 represents

that portion of the apparatus at the _receiving_ station. The magneto

electric machine, and the pole changer, properly connected, are the

instruments of the _transmitting_ station. 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 between _r_ and _l_,

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:

A r r r r r | I or Y l l r l l | R r r r l l

B r r r r l | K l r r r l | S or Z r r l r l

C r r r l r | L r l r r r | T l l r l r

D r r l r r | M r r l l l | U r l l l r

E r l r l r | N l l l l l | V l r r l l

F l r r r r | O l r l l l | W l l l l r

G or J l r l r r | P l r l r l |

H r l r r l | Q l l r r r |

_Numerals._

1 r l l l l | 6 r l l r r

2 r r l l r | 7 l l l r l

3 r l r l l | 8 l l r r l

4 r l l r l | 9 l r r l r

5 l l l r r | 0 l r l l r

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.

_Experiment of Messrs. Taquin & Ettieyhausen._[28]

“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.

[28] From the Polytechnic Central Journal, 1838.

_Electro Magnetic Printing Telegraph, invented by Alfred Vail,

September, 1837._

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 52 represents a front and side view of the instrument.

Figure 55 is a top view.

Figure 56 is a back view.

The same parts are represented by the same letters in the three views.

In figure 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 in figure 55, at X, X.) R is a brass standard

for supporting the lever, F, upon its axis, by means of two pivot

screws: _a_ and _a_ are 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 lower

end 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 and _r_. 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.

[Illustration: FIG. 52.]

There are 24 holes corresponding to the following letters of the

alphabet. 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:

figures 53 and 54 represent 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. In figure

54 is 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 at _r_, 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.

[Illustration: FIG. 53. FIG. 54.]

Figure 55 represents 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, _a_ and _a_ its adjusting screws; _x′_ and _x′_ its axis;

_k_ and _k_ are the two upper coils of the two electro magnets at the

back part of the instrument for purposes hereafter to be described;

_x_ is the wire soldered to the plate buried in the ground; _p_ is the

wire proceeding to the battery; _c_ is the connecting wire of the two

electro magnets, _k_ and _k_; w is the support of the pendulum; _v_ is

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.

[Illustration: FIG. 55.]

[Illustration: FIG. 56.]

Figure 56 represents a back view of the instrument; _k_, _k_ and _k_,

_k_ are the coils of two electro magnets, surrounding the soft iron

bars, _d_, _d_ and _d, d_; _b_ and _b_ are the flat bars through which

_d, d_ and _d, d_ pass, and are fastened together by the screw nuts

_c, c_ and _c, c_. The right hand electro magnet is fastened to the

blocks, M and M, by the support, _f_ and _f_; from which proceeds a

bolt passing between the coils, _k_ and _k_, 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, and _l_ are 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 of

return, 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 at _x_. Thus

the wire is continuous from _w_ to _x_. From _x_, 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 at _p_, 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, figures

48, 49 and 50. 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 when _A type_, of one station, is vertical, the _A

type_, of the other station, is also vertical. Now, suppose one station

wishes to transmit to the other, the word _Boston_, for example: he

first 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 figures

53 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 the _vertical 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

word _Boston_, 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.

[29] A day’s work of a fair compositor in setting up type is 6,000 ems,

equivalent to 12,000 pieces, in ten hours, or 20 pieces per minute. A

very quick and expert compositor may set up 10,000 in the same time,

equal to 20,000 pieces, or 33⅓ pieces per minute. One em is equivalent

to about two pieces.

[30] The author has recently devised a new plan for printing with type,

in which the pendulum movement is dispensed with, and the motion of

the type wheel is dependent upon the control and government of certain

apparatus at the transmitting station. This controlling part is capable

of giving to the type wheel a most rapid movement, and from an estimate

made from some actual tests, the number of letters capable of being

printed, are increased much beyond the former plan, taking the message

already used as an example. Still he considers it inferior to that

mode, now adopted by Professor Morse.

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 the _first_ class, 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:

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

- - - - - - - P R -

- - - - I - N - - T

- - - - I - N - - -

- - G - - - - T

- E - - L - -

- E G - - R

A - - P

H

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 for _one

instrument_, but extremely slow for _thirteen 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 the

_same point_ upon the paper, _falling back_ and 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 the _same point_ in a second, and each resume their 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.

[31] Mr. Vail invented an instrument with this arrangement 16 years

ago, for the purpose of printing speeches as fast as delivered.

To the _second_ class, belong all those which print in letters of an

hieroglyphical character. The _first_ plan 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 the _standard number_ of 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 plan_ consists in using four wires, four electro magnets,

four type levers, and the telegraphic characters of the third table.

The first 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 the _third_ class, 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 figures 52, 55 and 56. 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:

Letters per Cost. Number of On Morse’s No.

minute. wires. plan.

1st Class. { 1st plan, 480 $26,000 13 780 1

{ 2d “ 240 26,000 13 780 2

2d Class. { 1st plan, 60 2,000 1 60 3

{ 2d “ 80 4,000 2 120 4

{ 3d “ 85 6,000 3 180 5

{ 4th “ 103 8,000 4 240 6

{ 5th “ 120 10,000 5 300 7

3d Class. 1st plan, 37 2,000 1 60 8

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 the _single instrument_, with 13

_wires_. 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

the _electro 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 a

lever, 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, a _complication_.

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.

_Wheatstone’s Electric Needle Telegraph, invented in 1837._

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 figures 27,

28 and 29. Figure 57 is 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 on the 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 the _letters_, the deflection

of two needles are required, but for the _numerals_, one needle only.

The letter intended to be noted by the observer, is designated, in the

operation of the telegraph, by the _joint deflection_ of 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.

[Illustration: FIG. 57.]

We will now proceed to describe the arrangement of the springs and

buttons upon the platform, C, C, figure 58, (representing a top

view,) by the operation of which, any two needles may be deflected to

designate a letter, or one needle to designate a numeral.

[Illustration: FIG. 58.]

The numbers 6, 1, 2, 3, 4 and 5, represent keys of thin brass, and

elastic, and are each fastened to a wooden support, D, D, by means

of two screws. These keys are continued under and project beyond,

the brass bar, L and L, which is supported by two standards, R

and R. Whenever these keys are not pressed upon, they are each in

_metallic contact_ with the _bar_, R and R. The numbers 7, 8, 9,

10, &c. represent ivory buttons with a metallic stem beneath them,

passing through a hole in the spring, or key, and on the lower side

of the spring the stem is enlarged, so as to form a kind of hammer,

designed to make a metallic contact with the two brass bars, beneath

the springs, and represented as supported by the standards, N and N

and P and P. Each of the buttons have a small wire spiral spring, to

which they are fastened, and the small spring is itself fastened to the

larger spring. O represents the galvanic battery, with its poles in

connection with the two metallic bars, N and P.

Figure 59 represents a side view of the key arrangement. F is the

platform. E the wooden support of the six keys. H is the larger spring,

or key, secured to the support by screws, _h_. The spring is observed

to project beyond the metallic cross bar, L, after passing beneath it.

R is the support of the cross bar, L. N and O are two of the ivory

buttons, upon their spiral springs, _a_ and _c_. Below the button, O,

is a shoulder, formed at _i_, upon the stem which passes through the

spring, H, and another shoulder is formed by the hammer, _u_, below

the spring. It will be observed, that two buttons of the same key are

never used at the same time. If the button, O, is to be pressed down,

the weaker spring, _c_, will permit it to descend until the upper

shoulder comes in contact with the larger spring, H, when more pressure

is applied, and that spring is brought down, breaking its contact with

the metallic cross bar, L, until the hammer, _u_, comes in contact

with the metallic plate, _n_, upon the support, K, and as the plate,

_n_, is connected with N pole of the battery, the connection is formed

with it. It will, however, be noticed, that the button, N, not being

pressed upon, _will not_, (though it descends with the larger spring,)

be brought in contact with the other plate upon the support, J, and

connected with the positive pole of the battery. To the end of each

spring, a wire, S, is soldered, the purpose of which will be shown

hereafter.

[Illustration: FIG. 59.]

[Illustration: FIG. 60.]

Figure 60 represents an end view of the key arrangement; _a_, _b_, _c_,

_d_, _e_, _f_, are the buttons, M and M the metallic cross bar, beneath

which are seen the ends of the six larger springs, 6, 1, 2, 3, 4 and

5. R and R are the supports of the bar, M and M. G is the platform. W

is the support of the metallic plates, with which the hammers of the

little keys, or buttons, come in contact. S the wire leading to the

battery.

Having shown the several parts of Mr. Wheatstone’s plan, we will

proceed to describe the arrangement of two termini, as prepared for

transmitting intelligence. Figure 61 represents the arrangement of one

station, which we may suppose to be PADDINGTON. Figure 62 represents

the plan of the other station, which we will suppose to be SLOUGH. The

distance between these two places is eighteen miles.

In figure 61, it will be seen, that a wire is soldered to the end of

each of the springs 6, 1, 2, 3, 4 and 5, and are respectively connected

with the five wires of the dial, and the common communicating wire,

number 6, which does not pass through the dial, nor is connected with

any of the galvanometers. On the right hand side of the dial, the wires

are extended until they are shown as broken. From this point to the

opposite one, figure 62, where the wires appear also as interrupted,

we may suppose 18 miles to intervene. The wires here proceed to the

dial of the Slough station, making their proper connections with their

respective galvanometers, and from thence are continued and soldered

to their springs of the key arrangement, with the exception of wire,

number 6, which passes direct to the key, 6, without going through the

dial case. In both figures, is represented the battery, O, consisting

of six cups. The wire from one pole of the battery is connected with

the N metallic plate, the other wire with the P metallic plate. While

none of the buttons are pressed down, the battery is _not_ in action,

and it will also be observed that the circuits are all _complete_. The

action of the keys, then, is this, by a single operation to break the

circuit formed with the cross bar, L, L, and, at the same time, bring

_into_ the circuit, the battery, O.

The following numbers, representing the buttons, are those necessary

to be pressed down, in order to signal the letters and numerals on the

dial:

_Letters._

For A, buttons 10 and 17. | For M, buttons 9 and 12.

“ B, “ 10 “ 15. | “ N, “ 11 “ 14.

“ D, “ 12 “ 17. | “ O, “ 13 “ 16.

“ E, “ 10 “ 13. | “ P, “ 15 “ 18.

“ F, “ 12 “ 15. | “ R, “ 9 “ 14.

“ G, “ 14 “ 17. | “ S, “ 11 “ 16.

“ H, “ 10 “ 11. | “ T, “ 13 “ 18.

“ I, “ 12 “ 13. | “ V, “ 9 “ 16.

“ K, “ 14 “ 15. | “ W, “ 11 “ 18.

“ L, “ 16 “ 17. | “ Y, “ 9 “ 18.

_Numerals._

For 1, buttons 7 and 10. | For 6, buttons 8 and 9.

“ 2, “ 7 “ 12. | “ 7, “ 8 “ 11.

“ 3, “ 7 “ 14. | “ 8, “ 8 “ 13.

“ 4, “ 7 “ 16. | “ 9, “ 8 “ 15.

“ 5, “ 7 “ 18. | “ 0, “ 8 “ 17.

[Illustration: FIG. 61. PADDINGTON.]

[Illustration: FIG. 62. SLOUGH.]

The direction of the current, when the letter V is to be signalled, is

this: pressing down the buttons, 9 and 16, at the Paddington station,

the fluid leaves the battery, O, along the wire to the cross bar, P;

then to the hammer of the button, 16; then to the spring, 4; then along

wire, 4, to the galvanometer, 4, and through it, deflecting the lower

half of the needle to the left; then along the extended wire, 4, to the

dial, and galvanometer, 4, of the Slough station, deflecting the lower

half of that needle to the left; then to wire, 4, leaving the dial, to

key, 4; then to the cross bar, L and L; and along the cross bar to key,

1; then to wire, 1; then to galvanometer, 1; and through it, deflecting

the lower half of the needle to the right; thence it proceeds along the

extended wire, 1, to the Paddington station; entering the dial to the

galvanometer, 1, deflecting the lower half of the needle to the right;

then along wire, 1, to the key, 1; then to button, 9; then to the cross

bar, N, beneath; and then to the negative pole of the battery, O. It

will be observed, that the needles of both stations, thus deflected,

point to the same letter, V. In Mr. Wheatstone’s arrangement, but one

person can transmit at the same time, although he uses six extended

wires. One must wait while the other is transmitting.

If a numeral is to be signalled, it is obvious, that but one

galvanometer is needed. We will, therefore, suppose that the needle, 1,

is vertical.

Let the buttons, 7 and 16, be pressed down, at the Paddington station.

The current then leaves the positive pole of the battery, O, to the

cross bar, P; then to the key, 4; then along wire, 4, to galvanometer,

4, deflecting the lower half of the needle to the left; from thence to

the Slough station to galvanometer, 4, deflecting the lower half of the

needle to the left; then to wire, 4; then to key, 4; then to the cross

bar, L and L, and along it to key, 6; then to wire, 6, and along the

extended wire to the Paddington station, to key, 6; then to the cross

bar beneath the button, 7; then to the negative pole of the battery, O.

The needles, 4 and 4, of both stations, are simultaneously deflected,

so as to point to the figure, 4, on the margin of the dial.

In this manner the circuits required for each letter and numeral may

be traced out. Now, suppose the message to be sent from the Paddington

station to the Slough station, is this, “WE HAVE MET THE ENEMY AND

THEY ARE OURS.” The operator at Paddington presses down the buttons,

11 and 18, for signalizing upon the dial of the Slough station, the

letter W. The operator there, who is supposed to be constantly on the

watch, observes the two needles pointing at W. He writes it down, or

calls it out aloud, to another, who records it, taking, according to a

calculation given in a recent account, two seconds at least for each

signal. Then the buttons, 10 and 13, are pressed down, and the needles

are observed to point at E; and so for the remaining letters of the

sentence, U excepted, which has no letter on the dial.

The peculiarity of Mr. Wheatstone’s plan, is, the employment of six

wires for one _independent_ line of communication. The use of five

galvanometers, with their needles, by the deflection of which, 30

letters and numerals are pointed out. The messages are not recorded by

the instrument itself, but it is necessary that a person be constantly

observing the successive movements of the needles, and note them down

as they point to the signal. This plan was invented in 1837, and as

Prof. Wheatstone took out letters-patent in the United States, in 1840,

for this arrangement, it is a fair inference, that at that time, this

was his simplest and most perfect method.

_Steinheil’s Electric Telegraph._

Description of the magneto electrical telegraph, erected between

Munich and Bogenhausen, in 1837, by Dr. Steinheil,[32] Professor of

Mathematics and Natural Philosophy at the University of Munich, taken

from the Annals of Electricity, Magnetism and Chemistry, conducted by

William Sturgeon, London, April, 1839.

[32] Steinheil in the account he gives of his own telegraph, says,

“Gauss mentions a communication from Humboldt, according to which

Belancourt, in 1798, established a communication between Madrid and

Aranjuez, a distance of 26 miles, by means of a wire, through which a

Leyden jar used to be discharged, which was intended to be used as a

telegraphic signal.”

[Illustration: FIG. 63.]

A, A represents a vertical section, through the centre of the coil of

copper wire. C is the interior brass frame, round which the wire is

wound. B and B are the sides of the frame; I, I, I, I are four brass

tubes, soldered to the interior brass frame, and passing through the

centre of the coil to its exterior, with a screw cut in the end of

each; D and D are two permanent magnets movable on their axis, _a_ and

_b_. These spindles, _a_ and _b_, on each side of the magnets, pass

up the hollow of the tubes, and having their ends pointed, enter the

centre cavity of the four thumb screws, J, J, J, J, by which they are

supported, and delicately adjusted, so as to move easily and freely. L

and L are the ends of the wire leaving the coil. H and K are two ink

holders, attached to the magnets, which will be explained hereafter.

[Illustration: FIG. 64.]

Figure 64 represents a horizontal section of the coil, and magnets

D′ and D′, as above described, together with the other arrangements

of the instrument for receiving intelligence. The magnetic bars are

so situated in the frame of the multiplier, that the north pole, N′,

of the one, is presented to the south pole, S′, of the other. To the

ends which are thus presented to each other, but which, owing to the

influence they mutually exert, cannot well be brought nearer, there are

screwed on two slight brass arms, supporting little cups, H′ and K′.

These little cups, which are meant to be filled with printing ink, are

provided with extremely fine perforated beaks, that are rounded off in

front. When printing ink is put into them, it insinuates itself into

the tube of their beaks, owing to capillary attraction; and without

running out, forms at their apertures, a projection of a semiglobular

shape. These little cups are seen at H′ and K′, and in figure 63 at H

and K. The horizontal section shows, also, the position of the magnets

in the instrument, with the beaks of the pens near the continuous band,

or ribbon of paper, E, which is brought in front of the pens vertically

from below, over a small roller, F. The paper is supplied from a large

roll on a wooden cylinder, upon which is a cog wheel, and connected

with a train of wheels and a vane, to regulate the rate of supply. The

paper is drawn along before the pen by being wound upon a cylinder,

T, concealed by the paper, and on the same shaft with the barrel, M,

upon which is wound a cord supporting a weight, N, below. The shaft is

supported in the standards, _o_ and _o_, which are fastened to a plate

of brass, P and P, also secured to the platform of the instrument. The

barrel revolves in the direction of the arrow upon it.

When the electricity is transmitted through the coil of the indicator,

both magnetic bars, D′ and D′, make an effort to turn in a similar

direction upon their vertical axis, _a_ and _b_. One of the cups of

ink, therefore, advances towards the paper, while the other recedes. To

limit this action, two plates, V and V′, are fastened at the opposite

ends of the free space, allowed for the play of the bars, and against

which the other ends of the bars press. Only the end of one bar can,

therefore, start out from within the multiplier at a time, the other

being retained in its place. In order to bring the magnetic bars back

to their original position, as soon as the deflection is completed,

recourse is had to two small movable magnets, a portion of which is

seen at N and S, whose distance and position are to be varied till

they produce the desired effect. This position must be determined by

experiment, inasmuch as it depends upon the intensity of the current

called into play.

Having described the instrument, its operation is as follows: At the

_transmitting_ station is the pole changer, such as we have described

in figures 48, 49 and 50, and the magneto electric machine such as is

described in figures 45, 46, and 47, and are properly connected, and

in the circuit with the instrument of the _receiving_ station, such

as we have just described. For one single circuit, one wire extends

from the transmitting to the receiving station, the return half of the

circuit is the earth. Thus the current passes from the generator along

the extended wire to the receiving station, and to the copper plate,

then returns through the ground to the copper plate of the transmitting

station, to the pole changer and the magneto electric machine. Thus the

circuit is complete.

It is clear, from what has preceded, that when the pole changer is

thrown to the left side, (the machine being in operation,) the fluid

is made to pass in the direction of the arrows, shown at P and N. Then

the N′ pole of the left hand magnet advances with its pen, K′, to the

paper, E, and a dot is made, and the S′ pole of the right hand magnet

recedes with its pen, H, from the paper, until the other end of the

magnet strikes the stop, V′. Now, if the letter to be formed, requires

two dots in succession from the same pen, the circuit is broken, and

the fixed magnets, N and S, bring back the deflecting magnets, D′ and

D′, to their former position, when the pole changer is again thrown to

the left, and the magnets are deflected in the same manner as at first.

Thus two dots are marked upon the paper, on the right hand line. But,

now, let the pole changer be thrown to the right hand side, and the

current is reversed. The N′ pole of the left hand magnet, with its pen,

K, recedes from the paper until it strikes the stop, V, and the S pole

of the right hand magnet, with its pen, H′, advances to the paper and

makes its dot upon it on the _left_ hand line. The pole changer is then

instantly brought to the middle position, and the magnets resume their

natural place, by the assistance of the stationary magnets, N and S.

The sign which has been marked upon the paper during this operation is

··

· and represents 9.

The following represents Mr. Steinheil’s telegraphic alphabet:

· ·· · ·· ·· ···· · · · · ·

· · ·  · · · · ···· · · ·· ··

A B D E F G H CH SCH I K L

··· ·· ·  · ·· · · · · · ··

··· ·· ·· ·· · · · · ··

M N O P R S T V W Z

··· · ·· ·· · ··· · · · · ··

· · · · ··· · ·· ·· · ··· · ···

1 2 3 4 5 6 7 8 9 0

_Masson’s Electric Telegraph._

“In 1837, M. Masson, Professor of Philosophy at Caen, made trial of

an electric telegraph, at the college of that city, for a distance of

about 600 metres. He employed, for developing the galvanic current,

an electro magnetic apparatus, similar, on the contrary, to that of

Mr. Pixii, and made it act on magnetic needles placed at two ends of

the circuit. Since that time, however, M. Masson has endeavoured to

simplify and gradually improve his apparatus.”[33]

[33] Report of the Academy of Industry, Paris, 1839.

_Davy’s Needle and Lamp Telegraph._

The following extracts from the London Mechanic’s Magazine, vol. 28,

page 296 and 327, 1837, is all the description we are able to find in

relation to it:

“There is a case, which may serve as a desk to use in writing down

the intelligence conveyed; and in this, there is an aperture about

sixteen inches long, and three or four wide, facing the eyes, perfectly

dark. On this the signals appear as luminous letters, or combinations

of letters, with a neatness and rapidity almost magical. The field of

view is so confined, that the signals can be easily caught and copied

down without the necessity even of turning the head. Attention, in

the first instance, is called by three strokes on a little bell; the

termination of each word is indicated by a single stroke. There is

not the slightest difficulty in decyphering what is intended to be

communicated.”

_Extract from page 327._

“In front of the oblong trough, or box, described by your

correspondent, a lamp is placed, and that side of the box next the

lamp is of ground glass, through which the light is transmitted for

the purpose of illuminating the letters. The oblong box is open at the

top, but a plate of glass is interposed between the letters and the

spectator, through which the latter reads off the letters as they are

successively exposed to his view. At the opposite side of the room,

a small key board is placed, (similar to that of a piano forte, but

smaller,) furnished with twelve keys; eight of these have each three

letters of the alphabet on their upper surfaces, marked A, B, C; D, E,

F; and so on. By depressing these keys in various ways, the signals or

letters are produced at the opposite desk, as previously described, how

this is affected is not described by the inventor, as he _intimated_

that the construction of certain parts of the apparatus _must remain_

SECRET. By the side of the key board, there is placed a small galvanic

battery, from which proceeds the wire, 25 yards in length, passing

round the room. Along this wire the shock is passed, and operates upon

that part of the apparatus which discloses the letters or signals.

The shock is distributed as follows: The underside of the signal keys

are each furnished with a small projecting piece of wire, which, on

depressing the keys, is made to enter a small vessel, filled with

mercury, placed under the outer ends of the row of keys; a shock is

instantly communicated along the wire, and a letter, or signal, is as

instantly disclosed in the oblong box. By attentively looking at the

effect produced, it appeared as if a dark slide were withdrawn, thereby

disclosing the illuminated letter. A slight vibration of the (apparent)

slide, occasionally obscuring the letter, indicated a great delicacy

of action in this part of the contrivance, and although not distinctly

pointed out by the inventor, is to be accounted for in the following

manner: when the two ends of the wire of the galvanic apparatus are

brought together, over a compass needle, the position of the needle is

immediately turned, at right angles, to its former position; and again,

if the needle is placed with the north point southward, and the ends

of the wire again brought over it, the needle is again forced round to

a position at right angles to its original one. Thus, it would appear,

that the slide or cover over the letters, is poised similarly to the

common needle, and that by the depression of the keys, a shock is

given in such a way as to cause a motion from right to left, and _vice

versa_, disclosing those letters, immediately, under the needle so

operated upon.”

_Alexander’s Electric Telegraph, from the (Scotsmen) Mechanic’s

Magazine, Nov. 1837._

“A model to illustrate the nature and powers of this machine was

exhibited on Wednesday evening at the Society of Arts in Edinburgh.

The model consists of a wooden chest, about five feet long, three

feet wide, three feet deep at the one end, and one foot at the other.

The width and depth in this model are those which would probably be

found suitable in a working machine, but it will be understood that

the length in the machine may be a hundred or a thousand miles, and

is limited to five feet in the model, merely for convenience. Thirty

copper wires extend from end to end of the chest, and are kept apart

from each other. At one end (which, for distinction’s sake, we shall

call the south end) they are fastened to a horizontal line of wooden

keys, precisely similar to those of a piano forte; at the other, or

north end, they terminate close to thirty small apertures, equally

distributed in six rows of five each, over a screen of three feet

square, which forms the end of the chest. Under these apertures on

the outside, are painted, in black paint, upon a white ground, the

twenty-six letters of the alphabet, with the necessary points, the

colon, semicolon, and full point, and an asterisk, to denote the

termination of a word. The letters occupy spaces about an inch square.

The wooden keys, at the other end, have also the letters of the

alphabet, painted on them in the usual order. The wires serve merely

for communication, and we shall now describe the apparatus by which

they work.

This consists, at the south end, of a pair of plates, zinc and copper,

forming a galvanic trough, placed under the keys; and at the north end,

of thirty steel magnets, about four inches long, placed close behind

the letters painted on the screen. The magnets move horizontally on

axes, and are poised within a flat ring of copper wire, formed of the

ends of the communicating wires. On their north ends they carry small

square bits of black paper, which project in front of the screen,

and serve as opercula, or covers, to conceal the letters. When any

wire is put in communication with the trough at the south end, the

galvanic influence is instantly transmitted to the north end; and in

accordance with the well known law, discovered by Oersted, the magnet

at the end of that wire instantly turns round to the right or left,

bearing with it the operculum of black paper, and unveiling a letter.

When the key, A, for instance, is pressed down with the finger at the

south end, the wire attached to it is immediately put in communication

with the trough; and at the same instant, letter A, at the north end

is unveiled, by the magnet turning to the right, and withdrawing the

operculum. When the finger is removed from the key, it springs back to

its place; the communication with the trough ceases; the magnet resumes

its position, and the letter is again covered. Thus by pressing down

with the finger, in succession, the keys corresponding to any word or

name, we have the letters forming that word, or name, exhibited at the

other end; the name VICTORIA, for instance, which was the maiden effort

of the telegraph on Wednesday evening.”

[Illustration: FIG. 65.]

The above description is all that we have been able to obtain in

relation to this plan of an electric telegraph and here introduce,

figure 65, to illustrate it. The 30 needles are represented on the

screen, each carrying a shade, which conceals the letter when the

needle is vertical. The needle belonging to the letter F, is, however,

deflected, and the letter is exposed. The screen is supposed to be at

the _receiving_ station. To the left hand of the screen, 30 wires, _e,

e_, are seen joined to one, _a_; the other 30 wires, _d, d_, are seen

below the screen. These wires may be supposed to extend many miles, and

to be joined with their corresponding wires, _c_, and also _v, v_, of

the _transmitting_ station, where it will be observed, the wire, _c_,

connects with the battery at one pole, and from the other pole a wire

is continued and soldered to the metallic plate, _o, o_, which extend

under all the 30 keys, _i, i_. These keys are each insulated, at their

extremity, by being fastened to a wooden standard, L, L, to which a

wire is soldered. Now, suppose the key, F, is pressed down, (the sixth

key from the left,) the fluid then passes from the battery, B, through

the wire to _o_, the plate; then to the key in contact with it; then to

its wire, marked by the arrow; thence through the extended wire to its

corresponding wire at the receiving station, denoted by the arrow; then

through the coils of the multiplier, deflecting the needle, F; then

returns through its wire, at the left, to the common wire, _a_; then

through the extended wire to C, and the battery, of the transmitting

station. In this manner any letter upon the screen may be indicated.

_Extract from the Report of the Academy of Industry, in reference to a

suggestion of M. Amyot of an Electric Telegraph._

“M. Amyot announced, in a letter addressed to the Academy of Sciences,

in April, 1838, that he also proposed to construct an electric

telegraph. It was to consist of a single current, which would move

a single needle, which needle would of itself write on paper, with

mathematical precision, the correspondence which might be transmitted

to the other extremity, by a simple wheel on which it should be

written by means of points, differently spaced, the same as they are

on the barrels of portable organs. In order to send any news then,

he required to write, by means of movable characters, which must be

constructed in a certain manner, and immediately it would be repeated

and transcribed at the place where he wished to address it, on paper,

which could be put into the hands of persons specially employed to

transmit despatches. But all that method of execution, which it seems

ought to move is clock work, not having been sufficiently described

by the author, the _most vague uncertainty_ yet reigns as to the true

construction of that apparatus, which appears to us to have been for

M. Amyot, rather the occasion, than the end, of this communication;

for indeed he attempted to make the possibility admitted of

establishing a universal telegraphic language of his invention.”

_Edward Davy’s Electric Telegraph._[34]

The following description of Mr. Davy’s telegraph is taken from his

specification and drawings, published in the Repertory of Patent

Inventions. Although the specification has given the basis of his plan,

yet the description contained therein, and the drawings representing

his plan, are so obscure and deficient, that to have given it to

the public in that form, would have represented it as perfectly

impracticable. He has failed to state the number of signals which it

is capable of giving. He has committed great errors in the arrangement

of his wires for producing signals. He has introduced two keys, which

produce the same signals as two others in the same arrangement. He

has employed three extended wires for communicating from one station

to another station, and by his arrangement of them, could not have

obtained more than four signals. He has also very obscurely described

his escapement, by which his marking cylinder is made to advance one

division at a time for receiving the signals. This latter difficulty,

however, we have been enabled to clear up, by a description of it in

a work published by Mr. Bain. Notwithstanding the imperfections and

obscurities of his specification and drawings, we have endeavoured to

carry out his plan, and give it a practical shape, perhaps, as Mr. Davy

originally designed it.

[34] From the Repertory of Patent Inventions, No. lxvii. New Series,

London, July, 1839.—Sealed, July 4th, 1888.

As it is now described, there are 26 signals, or marks, indicating

letters. The employment of four wires instead of three, or if Mr. Davy

chooses to use for the common communicating wire the ground, which is

perfectly practicable, it will reduce the number to three, the number

he has specified. We have introduced one key more, and so arranged the

two superfluous keys as to make them available. With this preliminary,

we will proceed with the description.

[Illustration: FIG. 66.]

[Illustration: FIG. 67.]

Figure 66 represents a top view of the arrangement of the wires,

mercury cups, and batteries of the _transmitting station_. The close

parallel lines represent the wires, of which D, A, B and C are those

which proceed to the receiving station. 1′, 2′ and 3′ are the three

batteries, of which, P and N are their respective poles. The small

circles formed at the termination of the wires, and marked 7, 1, 10, 2,

20, &c. are mercury cups, in which the terminating wires are immersed.

The wires 1 and 20, and 2 and 10, &c. which cross each other, are not

in contact, but perfectly insulated. The wires shown in this figure,

are all secured permanently, with their mercury cups, to one common

base board. The letters H, J, K, M, O and U represent the places of the

six finger keys, used in transmitting signals. There is, also, another

key at 7, for uniting the wire, D and D. In this figure, however,

the keys themselves are omitted, in order to render more clear the

arrangement of wires under and around them. Another figure, 67, is

here introduced to illustrate the plan of one set of wires and their

two keys. In figure 67 is represented, in a top view, the two wooden

keys, A and B, and their axes, at E and F. G is the battery, of which,

9 is the positive pole, and 10 the negative pole. The small circles,

marked 1, 2, 3, 4, 5, 6, 7 and 8 represent the mercury cups. C and C′,

and also, D, are the extended wires. The keys, A and B, have each two

wires, passing at right angles through the wooden lever. The wires of

the key, A, are marked 1 and 2, and 5 and 6, and those of the key, B,

are marked 3 and 4, and 7 and 8. These wires, directly over the mercury

cups, are bent down a convenient length, so as to become immersed in

the cups, when the lever is depressed, and rise out of them, when the

lever is elevated. Now, if the key, A, is depressed, the cup, 1, is

brought in connection with cup 2; and 5 is connected with 6, by the

wires, supported by the lever, being immersed in the mercury; and the

key, B, not being depressed, there is no connection of the cup 3 with

4; or 7 with 8. At X and X, under the lever, are springs, which keep

the lever elevated; and, consequently, the wires out of the cups, when

the keys are not pressed down.

[Illustration: FIG. 68.]

Figure 68 represents a side view of the lever, or key, A, and its

axis at E. R is the platform supporting the standard of the axis;

the stationary wires; the battery, G; and the mercury cups, _a, a_

and 10. X is the spiral spring, for the purpose of carrying back the

lever, after the finger is taken off and sustaining it in its elevated

position. Through the centre of the spiral, passes a rod, with a head

upon it at the top of the lever, to limit its upward motion. At its

lower end, the rod is secured in the platform, R. 4 and 8 are the two

wires supported by the lever, A, and are seen to project down directly

over the mercury cups, _a_ and _a_, so that by depressing the key, they

both enter the cups and form a metallic connection. The key, B, figure

67, has the same fixtures and is similarly arranged as the key, A,

represented above.

[Illustration: FIG. 69.]

Figure 69 represents a top view of die arrangement of multipliers

at the _receiving_ station. R′, R′ and R′; R, R, and R are six

magnetic needles, or bars, each of which move freely upon a vertical

axis passing through their centres. The lower point of their axes

is immersed in cups of mercury, in which also terminate the wires,

I, I, I and L, L, L. The wires, D″, A′, B′ and C′, are those coming

from the _transmitting_ station. A′, B′ and C′, each enter the needle

arrangement, and first passing from left to right, over the magnetic

bars, R′, R′ and R′, in the direction of their length, then down and

under and round, making many turns, leave these three needles and

pass _under_ the needles, R, R and R, and in like manner from right

to left round them, making a number of turns, then pass off and unite

together, in the wire, 9, which is a continuation of D″. This wire is

called the _common communicating wire_,[35] and the wires, A′, B′ and

C′ are called _signal wires_. At right angles, there projects from each

magnetic bar, a metallic tapered arm, which rests against the studs,

V, V, V, V, V, V, when the needle is undisturbed. But when the needles

are made to move in the direction, to carry the arms to the left, they

are brought in contact with the metallic stops, S, S, S and T, T, T.

To each of these stops, it will be observed, a wire is soldered, and

continued respectively from S, S, S to ̈1, ̈3, ̈5, and from T, T, T to

̈2, ̈4, ̈6. It will also be observed, that from each of the mercury

cups below the magnetic bars, the wires, I and L, and I and L, and

I and L, proceed and unite in pairs at, L, L, L; these three united

wires are then continued, and the whole are joined in one at 8. The

wires, ̈1, ̈2, ̈3, ̈4, ̈5, ̈6, are continued, in a manner hereafter

to be described, and are connected with one pole of a battery. The

wire, 8, is also continued and connected with the other pole. So that

if any one of the needles should be made to move its arm to the left,

thereby coming in contact with its metallic stop, the circuit would be

complete and the current would pass along the wire, ̈1, for example,

to the metallic stop, then to the arm, and to the magnetic bar; then to

the axis; then to the mercury; then to the wire, I, and thence to the

wire, 8. In the same manner the current would pass if any other arm was

brought against _its_ metallic stop. All the wires represented in this

figure are permanently secured in their places upon a common platform.

[35] A′, B′ and C′ are also, occasionally, common communicating wires.

In order to understand the combined operation of the keys and needles,

figure 70 is here introduced. The right hand figure, is the same as

figure 69, and the left hand the same as figure 66.

[Illustration: FIG. 70.

_Transmitting Part of Receiving_ _Station. Station._]

The wires, D″, A′, B′ and C′, are detached from their corresponding

wires of the transmitting station, and it may be imagined that many

miles of wire intervene and connect the two. In the left hand figure,

those mercury cups above and below, 1 and 10, are joined by two

wires passing through a moving lever, in the same manner as has been

described in figure 67. We will, therefore, call the key, carrying

these two connecting wires, H. In like manner the key for the cups

above and below the numbers, 2 and 20, is called J; for 3 and 30, is

K; for 4 and 40, is M; for 5 and 50 is O; for 6 and 60, is U. The key

which connects the two mercury cups on the right and left of number 7,

of the wire, D″, is called 7. There are 7 keys; two for each battery,

1′, 2′ and 3′, and each wire, A′, B′ and C′; and one for the common

wire, D″.

It will now appear, that if the key, U and 7, are depressed, the cups

above and below, numbers 6 and 60; and the cups on each side of number

7, will be connected together so that the current leaving, P, or the

positive pole of the battery, 3′, goes to the lower cup, 50; then by

the stationary cross wire to upper cup, 6; then passes to lower cup,

6, by the wire supported by the lever, U, which is now pressed down,

and its ends immersed in the two cups; then along the wire, D, to the

left hand cup, 7; then to the right hand cup, 7, by the wire supported

by the lever, 7, and which is immersed in the two cups; then through

the extended wire to D″, of the _receiving_ station; then through 9,

to the two multiplying coils of the wire, C′, deflecting the arm of

the needle, R, to the right, against the stop, V; and the arm of the

needle, R′, to the left against the metallic stop, S, as indicated by

the arrow at S; then along the extended wire, back to the lower cup,

60, of the _transmitting_ station; then to upper cup, 60, through the

wire supported by the lever, U; then to N, the negative pole of the

battery, 3′.

It will be observed of the two needles, R and R′, in the circuit of the

same wire, C′, that if R is deflected to the right against the stop,

V, then R′ will be deflected to the left against the metallic stop, S.

The current, to produce these deflections, being through the wire C′,

in the contrary direction to that indicated by the arrow of the wire,

C′. But if R is deflected to the left against the metallic stop, T,

then R′ will be deflected to the right against the stop, V. The current

to produce these deflections, will then be through the wire, C′, in

the direction of the arrow of that wire. The same effect is produced

upon the two other pairs of needles of the wires, A′ and also B′. These

contrary movements of the two needles, when a _current_ is passing, are

produced by the coils being so wound, (see figure 69,) that the wire

passes round one needle in a contrary direction to what it does round

the other.

If, now, we depress the keys, O and 7, the cups above and below, 5 and

50, and on each side of number 7, will be connected. The fluid will

then pass from P or positive pole of the battery, 3′, to the lower

cup, 50; then through the key wire to upper cup, 50; then along the

extended wire, C′ to the _receiving_ station; then through the coils

of the multipliers, deflecting the arm of the needle, R, to the left

against the metallic stop, T; and the arm of the needle, R′, to the

right against the stop, V, as indicated by the arrow at V; then to

wire, 9 and D″; then along the extended wire back to the _transmitting_

station, to the right hand cup, 7; then by the key wire to the left

hand cup, 7; then to wire, D; then to upper cup, 5; and through the key

wire to lower cup, 5; then by the cross wire to upper cup, 60, and then

to N, or negative pole of the battery.

We have now shown the route of the current, when the keys, U and 7; and

the keys, O and 7, were depressed. It will be observed, that when the

keys, U and 7 were used, the current through the wire, D″, was from

_left_ to _right_; and when the keys, O and 7, were used, the current

was from _right_ to _left_. Thus, by means of the six keys, the current

of each battery may be made to pass in either direction through the

_common communicating_ wire, D″. By the keys, U, M, J, with 7, the

current is made to pass from _left_ to _right_ along the wire, D″. By

the keys, O, K, H, with 7, the current is made to pass from _right_

to _left_ along the wire, D″. By these six keys, all those various

deflections of the six needles are produced, which are necessary

to close the circuit of such of the wires, ̈1, ̈2, ̈3, ̈4, ̈5, ̈6, with

the wire, 8, as are required for marking the signals desired, on an

instrument now to be described.

[Illustration: FIG. 71.]

[Illustration: FIG. 72.]

Figure 71 represents a top view of that part of the instrument at the

_receiving_ station, by which the signals are recorded. The seven

wires on the left of the figure are a continuation of those wires,

marked ̈1, ̈2, ̈3, ̈4, ̈5, ̈6, and 8, in figure 70. The first six pass

through a wooden support, _b_ and _b_, and terminate upon the edge of

the platinum rings, _a_, _a_, _a_, _a_, _a_ and _a_, forming a metallic

contact. The six platinum rings surround a wooden insulating cylinder,

_t_, which revolves upon axes in the standards, _h_ and _i_. The rings

are _broad_ where they come in contact with the wooden roller, and are

bevelled to an _edge_ where they come in contact with the six wires.

Y represents a compound battery, with one pole of which, wire 8, from

the needle arrangement, figure 70, is connected, and from the other

pole the wire proceeds to the electro magnet, Z, Z; it then passes on

and is brought in connection with the metallic cylinder, _d_, at the

point, _g_. The cylinder, _d_, revolves upon axes, and is supported in

the standards, _k_ and _l_. To the cylinder is attached a barrel, _n_,

upon which is wound a cord, supporting the weight, _e_, by which the

cylinder is made to revolve. C′, C′, represents a prepared fabric, such

as calico, (impregnated with hydriodate of potass and muriate of lime,)

and is placed between the platinum rings, _a, a, a, a, a, a_, and the

metallic cylinder, _d_; _o_ is a cog wheel upon the end of the axis of

the cylinder, _d_, and is connected with other machinery, omitted here,

but shown in figure 72, which is a side elevation of part of figure

71: _o_ is the cog wheel, (figure 72,) on the arbor of the cylinder,

_d_. B and B, are the two sides of the frame containing the clock work,

and is secured to the platform, R: _d_ is a part only of the metallic

cylinder, upon which is seen a portion of the prepared fabric, K. The

cog wheel, _o_, drives the pinion, A, on the shaft of the fly vane,

G. M is an end view of the electro magnet, (represented by Z, Z, in

figure 71,) of which N and P are the two ends of the wire composing

the helix. D is its armature, constructed so as to move upon an axis

represented by two small circles. To the armature are connected, and

capable of moving with it, two arms, E and I, which project, so as to

come in contact with the pallet, _a_, of the fly, G. F is a spiral

spring, one end of which is fastened to the armature, D, and the other

passes through a vertical hole in the screw, S, in the bar, T, by which

the armature is held up in the position now seen, when not attracted

by the electro magnet. Now, if the wires, N and P, connected with

battery, Y, (figure 71,) have their circuit closed, the current passing

through the helix of the magnet, M, brings down the armature, D, in

the direction of the arrow, which raises the arm, I, against which the

pallet, _a_, of the fly vane, is resting, and releases the fly. It then

makes a half revolution and is again arrested by the pallet against

the lower arm, E, and the cylinder, _d_, with its fabric, has advanced

a half division. If the circuit is now broken, the armature, D, is

carried up by the spring, F, at the same time the arm, E, releases the

pallet, _a_, and the fly makes another half revolution, and is again

stopped by the arm, I. The cylinder has now made another advance of

half a division, which, together, makes a whole division the fabric has

advanced. The purposes for which this is designed will now be described.

[Illustration: FIG. 73.]

Figure 73 represents a top view of the whole apparatus of the

_receiving_ station. The fabric, C′, C′, is marked in equal divisions

across it, and in six equal divisions, in the directions of its

length, thus marking it into squares. Each platinum ring, _a, a, a_,

&c. (when the instrument is not in operation,) is in contact with the

fabric at the _middle_ of the squares across the fabric. It will be

observed, that the wires ̈1, ̈2, ̈3, ̈4, ̈5, ̈6 are in connection with

the battery, Y, and the circuit complete, except at the arms of the

needles. Suppose, for example, the arm of the needle, R′, of the wire,

C′, is brought up against the stop of the wire, ̈5, at S; the circuit

is then closed, and the current leaves the battery, and passes to

the electro magnet, (causing the cylinder and fabric to move half a

division,) then to the metallic cylinder, _d_; then through the fabric,

_c′, c′_, resting upon the cylinder, (where it is in contact with

the platinum ring, _a_, of the wire, ̈5,) then to the platinum ring;

then to wire ̈5; then to the metallic stop, S; then to the arm of the

needle, R′, along its axis to the mercury; then to the wire, I; then

to wire, 8, and to the other pole of the battery, Y. Thus a current is

passed through the prepared fabric, and a mark produced thereon, in the

middle of its square. If the circuit is now broken, the cylinder moves

another half division, which will bring the rings to the centre of the

squares, ready for the next signal.

But one battery, Y, is used for all the six circuits, formed with the

wire, 8; so that, when three of the circuits are closed at the same

instant, as will be shown hereafter, the current passes through the

three wires of their respective circuits, making each their appropriate

mark upon the fabric.

We now proceed to describe the manner of operating with the two

instruments, at their respective stations: and, first, we must here

designate each needle by its own peculiar mark of reference. Let the

two needles upon the wire, A′, be denoted by, A, S and A, T; those of

the wire, B′, by B, S and B, T; and those of the wire, C′, by C, S and

C, T. It will appear obvious, from the foregoing description, that

but _one_ needle of each _wire_, A′, B′, C′, can be made to close its

circuit at the same instant. However, _two_ needles, or _three_ needles

of _different wires_, may close their circuits at the same instant,

but no higher number than three. The various combinations of _one_

mark, _two_ marks, and _three_ marks, upon the same row of six cross

divisions of the fabric, constitute the characters representing letters.

[Illustration: FIG. 74.