340 Description of the French Telegraphs 



tfiegraph, will consequently be three hundred and ninety- 

 one*. As only three bodies are cmplewed in the French 

 telegraph, it may therefore appear superior to the Admiraliv 

 telegraphs used in England, which by the combination of 

 double that number of bodies caw only make sixty-three 

 distinct signals, 



The meclianisni of the French telegraphs just described, 

 must either be imperfect, or the men employed in working 

 them must have been very unskilful, for the signals were 

 made and repeated in an awkward manner, wiih, what 

 seemed to me, much unnecessary loss of time; but these 

 defects, it will be evident, detract nothing from its merit 

 as an invention. In regard to the mechanical construction, 

 I could only ob.-erve that the arms, which are painted 

 black, and appear solid at a distance, are made in the fashion 

 of a Venetian blind, in order, it may be presumed, to di- 

 minish the action of the wind in bad weather. Each arm 

 has a counterpoise of thin materials painted, white, which, 

 unless the observer is very near the telegraph, becomes in- 

 visible. 



In the annexed Plate, fig. 1 shows the telegraph in a 

 state of rest, the dotted lines marking the several positions 

 in which the arms can be exhibiied. 



Figs. 2 and 3 are a specimen of the telegraph at work. 



Fig. 4 sho^vs the construction of one of the arms on a 

 larger scale, DE being the part which is fashioned like a 

 Venetian blind, and EF the counterpoise. 



From the above descriptiou it will appear, that the French 

 have adopted, in the arms of their new telegraph, the same 

 principle of motion used in the polygrammalic telegraph 

 invented by me, of which an account is contained in the 

 xxixth volun)e of this work ; the only difference being, 

 that in my telegraph two arms are placed on the same axis, 

 instead of one, to whicli they have confined themselves. 



Instead of using several posts, which appeared to me 

 the most eligible mode, a polygrammatic telegraph may 

 also be constructed upon one post. Fig. 5 shows how^ 

 this may be done, on comparison of which with my former 

 invention, (fig 6,) it will be seen that the same signals can 

 in some cases be nicule by both. 



The disadvantage attending a polygrammatic telegraph 



• A naval officer who ha« been lately employed in the Mediterratrtan 

 informs me, that he doca not believe that the arm A is ever shown ifi its 

 fourth position. I thmk 1 have seen it myseU' in that position, but am not 

 certain. If the French confine themselves to only six positions upon that 

 arm, the total number of signals will be reduced from 391 to 34'i. 



constructed 



