IMPROVEMENTS IN ELECTRIC TELEGRAPH APPARATUS
Year: 1866

page_text: PROVISIONAL SPECIFICATION left by William Clark at the Office of
the Commissioners of Patents, with his Petition, on the 20th October
1866. A communication from abroad by Joseph de Susini, Gentleman,
and Jean Marie Onésime Tamin, Doctor of Medicine, both of 29, Boulevart
St. Martin, Paris.
I, WILLIAM CLARK, of 53, Chancery Lane, in the County of Middlesex,
Engineer and Patent Agent, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN ELECTRIC TELEGRAPH APPARATUS," to be as.
follows:
These improvements in writing telegraph apparatus consist, 1st, in producing
a rapid rotary motion as opposed to the rectilinear motion of such apparatus,as
hitherto arranged; 2ndly, in simplifying the construction of the apparatus. Like
áll electro-chemical apparatus it is based on the property possessed by solutions,
of certain salts, such as nitrate of manganese, iodide of potassium, and others,.
of becoming decomposed by the electric current and of leaving colored marks on.
paper impregnated with such solutions, either by the elements of the salts.
becoming simply decomposed or forming other combinations to produce the
colored marks, and this without injuriously affecting the electrodes.
The Drawings annexed represent an improved apparatus arranged according
to this Invention, Figure 1 showing a vertical front elevation of a writing
telegraph apparatus, Figure 2 an end view, and Figure 3 a plan of the same.
The same letters serve for all three Figures.....

page_text: The apparatus consists of a train of wheels A, and a motive barrel a provided
with a spring or weight, and a flyer b. Motion is imparted by the traiu A
to a-metal cylinder B mounted in horizontal bearings, on which a metal
cylinder C bears, being free to turn on its axis; this latter cylinder consequently
partakes in the motion of B in such manner that if a strip of paper P be
inserted between them the motion of the said cylinders will carry it through
in the direction of the arrow. The strip P previously passes over another
metal cylinder D mounted parallel with those before mentioned and receiving
motion from the train A, the strip being held in contact with the cylinder D
by means of a comb E, composed of a certain number of platina points
isolated electrically and united to the line wires. The points of this comb
should be all of exactly the same length and in a straight line parallel with
the axis of the cylinder D. This comb is mounted like the cylinders in a
frame enclosing the working parts, and is inclined at an angle to the direction
of motion of the paper, in order to allow of its passing freely without tearing.
It will be evident that by employing two similar apparatus, each provided
with a comb, and working at the same speed, the two combs will traverse the
same surface on the strip simultaneously, the corresponding points of the two
combs being at all times at, corresponding points of the surfaces traversed.
In order to transmit autographic messages it is simply necessary to connect
the points of the combs of the two apparatus by a small cable F, containing
as many wires as there are points in the combs, and taking care to unite the
corresponding teeth of the combs by the same wire, a strip is then adapted
to the one apparatus to serve as a transmitter, and to the other a strip of
paper prepared in a solution of nitrate of manganese, iodide of potassiuni, or
other sensitive solution. The strip which is to serve as a transmitter should
be of metal (leaf tin or silver), on which the characters are traced in common
ink containing a large proportion of gum; the writing or other marks forms
the insulated part, while the groundwork will be the part conducting the
electricity; and in order that the insulated part may transınit the current to
the line, the circuit should be established in the following manner :-The two
combs are united as before mentioned by the line wires contained in the
cable, each of which wires is connected at the transmitting station with the
positive pole of a battery, while all the negative poles are united together and
placed in communication with the apparatus, which in its turn is connected
to the ground wire, the receiving apparatus communicating directly with the
ground wire. By this arrangement it will be seen that every time the points
of the transmitting comb are in contact with the metallic portion of the strip
serving to transmit the message, the current of the several batteries will make

page_text: the short circuit of the station, while, on the other hand, if one or more points
are brought in. contact with the marks or writing forming the insulated
portion, the current of the battery or batteries corresponding to these points
will make the long circuit and pass to the corresponding station from the
points to the prepared paper, and as these points form<positive electrodes
decomposition will take place, and the whole of the dots and marks traced
by the chemical decomposition produced by the electric current will reproduce
exactly the figures or characters traced on the transmitting strip.
In electro-chemical transmissions a counter current is always useful,
especially for obtaining greater clearness in the marks, as also for increasing
the rate of transmission. For this purpose I place a battery on the line wire
at the receiving station having its positive pole connected to the apparatus, the
battery power should be in proportion to the length of the line; if the line bo
very short I place a resistant on the ground wire at the receiving station next
the battery of the counter current, in order that the transmitting current shall
not branch off at the departure station when it is required to traverse the
short local circuit. A commutator of very simple construction serves to render
the apparatus suitable either for transmitting or receiving messages by
introducing in the circuit either the transmitting battery or the battery of the
counter current and the resistant before mentioned, dispensing in the latter
caso with the transmitting battery. In order that the points of the transmitting
comb shall be always in perfect contact with the cylinder D during the trans-
mission I divide this cylinder into two parts, a metallic part d for receiving,
and a part d' covered in india-rubber for transmitting, and I construct the
bearing E' of the comb so as to be enabled to bring the latter on to one or
other of the parts d or d, according to whether it is to act as a transmitter or
receiver. Although the strip in the case of transmission is not in direct
electrical communication with the cylinder, it however being metallic com-
municates with the apparatus which is connected with the united negative
poles of the batteries by means of the rotating cylinders B, C. The number
of points in the combs depends on the size of the writing it is desired to
produce, and the greater or less perfection required in the reproduction of the
said writing; generally, for writing not exceeding one-fifth of an inch in size,
twelve points are sufficient to preserve its distinctive features. When the
stations are only at short distances apart, as in the case of two stations in
one town, it is of advantage to add an extra wire to the cable to serve as a
ground wire.
This apparatus need not be synchronous in its action, as oven supposing
there be à difference of one-twentieth or even one-tenth in the speed of two

page_text: corresponding apparatus, the writing from this cause would only be spread.out
one-twentieth or one-tenth more in length, and if not identical would closely.
resemble the writing on the metallic. strip. This' imperfection in the system,
if it may be so termed, is however compensated for by the absence of any.
apparatus for regulating the synchronous action, which is always difficult, if
not impossible, to regulate at a distance, especially with the quick rate of trans-
mission obtained by this apparatus, which is calculated to transmit as many as
three hundred messages per hour.