TELEGRAPH. 
| mall tract of land before several persons of 
l be highest rank at the court of France. 
It was not, however, till the French revo- 
lution, that the telegraph was applied gene- 
rally to useful purposes. Whether M. 
Chappe, who is said to have invented the 
telegraph first used by the French about the 
end of i.793, knew any thing of Amontons’ 
[invention or not, it is impossible to say; but 
his telegraph was constructed on principles 
nearly similar. The manner of using this 
' telegraph was as follows : At the first station, 
which was on the roof of the palace of the 
Louvre at Paris, M. Chappe, the inventor, 
received in writing, from the committee of 
public welfare, the words t® be sent to Lisle, 
near which the French army at that time 
5 was. An upright post was erected on the 
: Louvre, at toe top of which were two trans- 
h verse arms, moveable in all directions by a 
single piece of mechanisn, and with incon- 
ceivable rapidity. He invented a number of 
positions for these arms, which stood as signs 
for the letters of the alphabet ; and these, 
for the greater celerity and simplicity, he re- 
duced in number as much a? possible. The 
j grammarian will easily conceive that sixteen 
signs {nay amply supply all the letters of the 
alphabet, since some letters may be omitted 
not only without detriment but with advan- 
tage. These signs, as they were arbitrary, 
could be changed every week ; so that the 
sign of B for one day might be the sign of M 
the next ; and it was only necessary that the 
persons at the extremities should Jcnow the 
key. The intermediate operators were only 
instructed generally in these sixteen signals; 
which were so distinct, so marked, so differ- 
t ent the one from the other, that they were 
easily remembered. The construction of the 
machine was such, that each signal was uni- 
formly given in precisely the same manner 
at all ames ; it did not depend on the ope- 
rator’s manual skill ; and the position of the 
arm could never, for any one signal, be a de- 
gree higher or a degree lower, its movement 
being regulated mechanically. 
M. Chappe, having received at the Louvre 
the sentence to be conveyed, gave a known 
signal to the second station, which was Mont 
Martre, to prepare. At each station there 
was a watch-tower, where telescopes were 
fixed, and the person on watch gave the sig- 
nal of preparation which he had received, 
j and this communicated successively through 
i all the line, which brought them all into a 
state of readiness. The person at Mont 
Martre then received, letter by letter, the 
sentence from the Louvre, which he repeated 
with his own machine ; and this was again 
repeated from the next height, with incon- 
ceivable rapidity, to the final station at Lisle. 
The first description of the telegraph was 
brought from Paris to Franckfort on the 
Maine by a former member of the parliament 
of Bourdeaux, who had seen that which was 
erected on the mountain of Belviile. As 
given by Dr. Hutton from some of the Eng- 
lish papers, it is as follows: AA is a beam or 
mast of wood placed upright on a rising 
ground (Plate Miscel. fig. 231), which is 
about 15 or 16 feet high. BB is a beam or 
balance moving upon the centre AA. This 
balance-beam may be placed vertically or 
horizontally, or any how inclined, by means 
©f strong cords, which are fixed to the wheel 
on the edge of which is a double groove 
o receive the two cords. This balance s 
about eleven or twelve feet long, and nine 
inches broad, having at the ends two pieces 
of wood CC, which likewise turn upon an- 
gles by means of four other cords that pass 
through the axis of the main balance, other- 
wise the balance would derange the cords ; 
the pieces C are ea. h about three feet long, 
and may be placed either to the right or left, 
straight, or square with the balance-beam. 
By means of these three the combination of 
movement is very extensive, remarkably sim- 
ple, and easy to perform. Below is a small 
wooden hut, in which a person is em- 
ployed to observe the movements of the 
machine. On the eminence nearest to this, 
another person is to repeat these movements, 
and a third to write them down. The time 
taken up for each movement is twenty se- 
conds ; of which the motion alone is four 
seconds, the other sixteen the machine is 
stationary. Two working models of this 
instrument were executed at Frankfort, and 
sent by Mr. W. Playfair to the duke of 
York ; and hence the plan and alphabet of 
the machine came to England. 
Various experiments were in consequence 
tried upon telegraphs in this country ; and 
one was soon after set up by government in 
a chain of stations from the admiralty-office 
to the sea-coast. It consists of six octagon- 
boards, each of which is poised upon an axis 
in a frame, in such a manner that it can be 
either placed vertically, so as to appear with 
its full size to (lie observer at the nearest sta- 
tion as in fig. 232, or it becomes invisible to 
him by being placed horizontally, as in fig. 
233, so that tire narrow edge alone is exposed, 
which narrow edge is from a distance invisi- 
ble. Fig. 232 is a representation of this tele- 
graph, with the parts all shut, and the ma- 
chine ready to work. T, in the officer’s 
cabin, is the telescope pointed to tire next 
station. Fig. 233 is a representation of the 
machine not at work, and with the ports all 
open. The opening of (he first port ex- 
presses a, the second b, the third c, the 
fourth d, the fifth e, and the sixth/, &e. 
Six boards make 36 changes, by the most 
plain and simple mode of working ; and they 
will make 27 more if more were necessary ; 
but as the teal superiority of the telegraph 
overall other modes of making signals con- 
sists in its making letters, we do not think 
that more changes than the letters of the al- 
phabet, and the ten arithmetical cyphers, are 
necessary ; but, on the contrary, that those 
who work the Telegraphs should avoid com- 
municate by words or signs agreed upon to 
express sentences ; for that is the sure me- 
thod never to become expert at sending un- 
expected intelligence accurately. 
This telegraph is, without doubt, made up 
of the best number of combinations possible ; 
rive boards would be insufficient, and seven 
would be useless. It has been objected to 
it, however, that its form is too clumsy to ad- 
mit of its being raised to any considerable 
height above the building on which it stands ; 
and that if * cannot be made to change its di- 
rection, and consequently cannot be seen but 
from one particular point. 
Several other telegraphs have been pro- 
posed to remedy these defects, and perhaps 
others to which the instrument is still liable. 
The dial-plate ©f a clock would make an ex- 
775 
cellent telegraph, as it might exhibit 144 
signs so as to be visible at a great distance. 
A telegraph on this principle, with only six 
divisions instead of twelve, would be simple 
and cheap, and might be raised twenty or 
thirty feet high above the building without 
any difficulty : it might be supported on one 
post, and therefore turn round, and the con- 
trast of colours would always be the same. 
We shall now conclude this article with a 
short idea of Mr. John Garnet’s most simple 
and ingenious contrivance-. This is merely a 
bar or plank turning upon a centre, like the 
sail of a windmill ; and being moved into any. 
position, the distant observer turns the tube 
of a telescope into the same position, by 
bringing a fixed wire within it to coincide 
with or parallel to the bar, which is a thing 
extremely easy to do. The cent..; of mo- 
tion of the bar has a small circle about it, 
with letters and figures around the circum- 
ference, and an index moving round with the 
bar, pointing to any letter or mark that the 
operator wishes to set the bar to, or to com- 
municate to the observer. The eye-end of 
the telescope without has a like index and 
circle, with the corresponding letters or other 
marks. The consequence is obvious ; the 
telescope being turned round till its wire- 
covers or becomes parallel to the bar, the in- 
dex of the former necessarily points out the- 
same letter or mark in its circle, as that of 
the latter, and the communication of senti- 
ment is immediate and perfect. The use of 
this machine is so easy, that it has been put 
into the hands of two common labouring-men, 
who had never seen it before, and they have 
immediately held a quick and distant conver- 
sation together. 
The more particular description and figure- 
of this machine, are as follows. ABDE 
(fig. 234) is the telegraph, on whose centre of 
gravity C, about which it revolves, is a fixed, 
pin, which goes through a hole or socket in 
the firm upright post G, and on the opposite 
side of which is fixed an index Cl. Concen- 
tric to C, on the same post, is fixed a wooden? 
or brass circle, of six or eight inches diame- 
ter, divided into forty-eight equal parts, 
twenty-four of which represent the letters of 
the alphabet, and between the letters, num- 
bers ; so that the index, by means of the 
arm AB, may be moved to any letter or num- 
ber. The length of the arm should be or 
3 feet for every mile of distance. Two re- 
volving lamps of different colours suspended 
occasionally at A and B. the ends of the 
arm, would serve equally at night. 
Lets* (fig. 235) represent the section of th£- 
outward tube of a telescope perpendicular tp 
its axis, and ,rx the like section of the sliding 
or adjusting tube, on which is fixed an index 
1 1. On the part ol the outward tube next to 
the observer, there is fixed a circle ot letters 
and numbers, similarly divided and situated 
to the circle in fig. 234 ; then the index 1 1, 
by means of the sliding or adjusting tube, 
may be turned to any letter or number. Now 
there being a cross hair, or fine silver wire, 
fg, fixed in the focus of the eye-glass, in the- 
same direction as the index I! ; so that when 
the arm AB (fig. 234) of the telegraph is view- 
ed at a distance through the telescope, the 
crosshair maybe turned, by means' of the 
sliding tube, to the same direction. of tne arm 
AB ; then the index I I (fig. 235) will point 
to the same letter or number on its own 
