Description of ihe French Telegraphs. 53^ 



lines parallel to the directions AP, AQ, AR ; and the part* 

 EF, EH, EG, of these right lines, comprised between the 

 point E and the planes BAG, CAD, DAB, represent 

 the uiagniiudes of the required forces P, Q, R ; for these 

 lines being three edges of a paralleloj)ipedon, they are 

 respectively equal to the other edges AB, AC, AD, which 

 are parallel to them. 



LV. Description of the French Telegraphs used on the 

 Coasts of Flanders, ^c. with Observations on the same, 

 and a Plan of a Polij gramma tic Telegraph on a new 

 Construction, By Capt, C. W. Paslev, of the Royal 

 Engijieers*. 



xIaving last year had an opportunity of observing the na* 

 lure of the French telegraphs used on the coast of Flanders, 

 of which no account has, to my knowledge, been published 

 in this country, a description of them may perhaps be ac- 

 ceptable to the public ; particularly as J am led to believe 

 that they have been very recently invented, or at least 

 established, and that they are now in general use through- 

 out the whole extent of coast of the French empire. 

 Various naval officers, whom I have consulted with a view 

 of obtaining information on the subject, agree, that it is 

 only a few years since these telegraphs first made their 

 appearance ; but I have not been able to ascertain the pre- 

 cise period. It does not seem, however, from what I have 

 learned, to be more than three years ago, since the system 

 of signals by masts, yards and balls, which f know was 

 formerly used on many parts of the enemy's coast, wa>i 

 abolished, in order to make room for this new establish- 

 ment. 



Every telegraph consists of one upright post, to which 

 are attached three arms exactly similar to each other, 

 moving each upon its own distinct spindle or axis. The 

 axis of one of these arms is near the head of the post. The 

 distance from the centre of motion of each of the two up- 

 permost arms to that of the one imrtiediately below it, is 

 rather less than double the length oi' one arm. The 

 highest of the three arms (A) can exhibit seven distinct 

 positions, but the other two arms (B and C) can only ex- 

 hibit six positions each. The total number of combiuH- 

 tions, or of distinct signals, which can be made by this 



• Communicated by Capt. P.nsley. 



y 2 tdegraph, 



