1839.]] Telegraphic Signals by induced electricity. J\5 



year, it will perhaps prove interesting to give a rapid historical outline 

 of the attempts which have been made to apply the various indications 

 of the electrical fluid as the medium of instantaneous communication 

 between distant places. For several of the following references I am 

 indebted to an article by Dr. Steinheils of Munich, translated in the 

 May number of Sturgeon's Annals of Electricity. 



Historical Notice. 

 1. — Telegraphs by common electricity. 



The first electrical telegraph on record was proposed by Winkler of 

 Leipzic, in 1746. He employed a Leyden jar which was discharged 

 through a single wire, a reach of the river Pleiss being included in 

 the circuit. Le Monnier afterwards made a similar experiment in 

 Paris, using a wire 12,789 feet long. In 1798, Betancourt laid a 

 wire between Madrid and Aranjuez, 26 miles distant, to serve for the 

 transmission of shocks by the Leyden phial. The pith ball electro- 

 meter was used by Lomand ; and the sparks from tin-foil on glass sur- 

 faces by Reiser about the same period. 



In 1826, Francis Ronalds, of Hammersmith, published a description 

 of a plan in which two clocks were employed, one at each terminal 

 station. Each clock had a moveable dial with twenty signals on its 

 circumference. As the required signal letter presented itself, a spark 

 passed at each station by the discharge of a Leyden phial. This plan, 

 though comprising, as I will point out in the sequel, the true principle 

 of a good system, was found useless in practice, as each sign was given 

 but once in each revolution. 



Such are the principal attempts hitherto made to effect the object in 

 view, by means of frictional electricity. At the Meeting of the Asi- 

 atic Society of Bengal, of June 1839, M. Adolphe Bazin presented a 

 project for effecting telegraphic correspondence by means of thirty 

 insulated conductors passing between the terminal stations, each 

 conductor representing a letter or number, so that by the rapid 

 succession of sparks correspondence could be effectually carried on. 

 With this M. Bazin connected an hydraulic apparatus for the convey- 

 ance of intelligence across rivers, and in other situations where frictional 

 electricity might not be suitable. 



M. Bazin's plans, although very ingenious, were altogether impracti- 

 cable, and as we shall afterwards establish, demanded thirty conductors, 

 where only one is actually requisite; moreover the impediments to 

 the use of common electricity are absolutely insuperable in all coun- 

 tries (Bengal for example) visited by periodical rains or inundations. 



