ELECTRIC TELEGEAPH. 



as already described, make a blue or brown line on this paper. 

 If the current were continuous and uninterrupted, this line would 

 be an unbroken spiral, such as has been already described ; but if 

 the current be interrupted at intervals, during each such interval 

 the pen will cease to decompose the solution, and no mark will be 

 made on the paper. If such interruption be frequent, the spiral, 

 instead of being a continuous line, will be a broken one, consisting 

 of lines interrupted by blank spaces. If the current be allowed 

 to act only for an instant of time, there will be a blue or brown 

 dot upon the paper ; but if it be allowed to continue during a 

 longer interval, there will be a line. 



Now, if the intervals of the transmission and suspension of the 

 current be regulated by any agency in operation at the station 

 of departure, lines and dots corresponding precisely to these 

 intervals, will be produced by the electro-chemical pen on the 

 paper, and will be continued regularly along the spiral line 

 already described. It will be evident, without further explana- 

 tion, that characters may thus be produced on the prepared paper 

 corresponding to those of the telegraphic alphabet already de- 

 scribed in the case of Morse's telegraph, and thus the language 

 of the communication will be 'written in these conventional 

 symbols. 



There is no other limit to the celerity with which a message 

 may be thus written, save the sufficiency of the current to effect 

 the decomposition while the pen passes over the paper, and the 

 pOAver of tHe agency used at the station of departure to produce, 

 in rapid succession, the proper intervals in the transmission and 

 suspension of the current. 



The succession of intervals of transmission and suspension of 

 the current on which the production of the written characters on 

 the prepared paper depends, may obviously be produced by the 

 key commutator (128),; and with that instrument at the station 

 from which the dispatch is transmitted, an agent can convey in 

 the same manner and with the same celerity as in the case of 

 the telegraph of Morse, or that of Froment ; and such is in fact 

 the manner in which dispatches are usually transmitted with this 

 apparatus. 



213. But this form of commutator, though perfectly efficient 

 so far as it goes, does not call into operation all that extra- 

 ordinary celerity which forms the prominent feature of this 

 invention, and of which a remarkable example has been 

 already mentioned in the case of the experiments performed by 

 M. Le Terrier and myself before the Committees of the Institute 

 and the Legislative Assembly at Paris, which were made with 

 these instruments, and, as we have stated, dispatches were 

 50- 



