OPTICAL TELEGRAPHY,. 
7 
engine were amongst these inventions, but no trace now remains 
of the results obtained in these researches. 
Towards the end of the seventeenth century, Amontons and 
also Marcel made some experiments, as we know, although the 
machines and the drawings of these inventors have been lost, 
and Marcel has not left even a description of his plan. He 
did not wish to have his method made public until it had been 
adopted by the king; but Louis XIV. was then old, and 
Marcel got no answer to his petition. Dupuis, the author of 
“L’Origine de Tous les Cultes,” in 1723, laid before the 
government a scheme of alphabetic telegraphy. It was not 
until ten years afterwards that he made a trial of it at Menil- 
montant in order to communicate between his house and that 
of a friend at Bagneux. When Chappe’s telegraph was laid 
before the Legislative Assembly in 1792, Dupuis, who was one 
of the members, abandoned his plan. 
In 1783, Linguet offered the French government a method 
of transmitting to the greatest distance intelligence of any 
kind, even long sentences, with almost the speed of thought. 
This plan, which Linguet thought would obtain his release 
from the Bastille, was tested before commissioners appointed by 
the government. It was not adopted, and no trace of it remains. 
Monge seems also to have proposed, before Chappe, a signal 
telegraph which was erected on the central pavilion of the 
Tuileries, but was never used. 
It seems therefore that many scientific men studied the art 
of signalling, before Chappe and his brothers introduced their 
system of optical telegraphy into France. Nearly all their 
predecessors were content to communicate a few words from 
one station to another station, and this is one reason why they 
failed. But in order to transmit a considerable number of 
signals to great distances, it is evidently requisite that the 
stations must be numerous. The brothers Chappe tried ex¬ 
periments among themselves with a rude apparatus for cor¬ 
responding by signs, consisting of a wooden rule turning on 
a pivot and carrying two smaller rules of half the size at 
its extremities. They afterwards made some attempts at 
transmitting signals by electricity. Claude Chappe, the 
most ingenious of the five brothers, had contrived a method 
of corresponding by help of two synchronous pendulums, 
