178 THE ELECTRIC TELEGRAPH. 



is that with which Leverrier and Lardner experimented before 

 the Committees of the Institute and Legislative Assembly at 

 Paris. A band of paper, punched with groups of holes forming 

 letters, conventional like those of the Morse alphabet, is 

 passed between a metal roller and contact point in such a 

 way that the point falls through the holes and comes in 

 contact with the top of the cylinder, thereby closing the 

 line. 



The messages are received upon a strip of chemically- 

 prepared paper passed between a style and metal cylinder. 



Lardner thus describes his results* : 



" Two wires, extending from the room in which we ope- 

 rated to Lille, were united at the latter place so as to form 

 one continuous wire, extending to Lille and back, making a 

 total distance of 336 miles. This, however, not being deemed 

 sufficient for the purpose, several coils of wire wrapped with 

 silk were obtained, measuring in their total length 746 miles, 

 and were joined to the extremity of the wire returning from 

 Lille ; thus making one continuous wire measuring 1,082 

 miles. A message, consisting of 282 words, was then trans- 

 mitted from one end of the wire. A pen attached to the 

 other end immediately began to write the message on a sheet 

 of paper moved under it by a simple mechanism, and the 

 entire message was written in full in the presence of the 

 committee, each word being spelled completely and without 

 abridgment, m fifty-two seconds, being at the average rate of 

 fire words and four- tenths per second. By this instrument, 

 therefore, it is practicable to transmit intelligence to a dis- 

 tance of upwards of 1,000 miles at the rate of 19,500 words 

 per hour." 



The alarm used with Bain's telegraph consists of two round 

 plates of glass of different sizes, struck by a hammer which 

 vibrates between them. The glass discs are supported from 

 their centres by two horizontal arms of an upright. The 

 hammer consists of a vertical tongue of brass turning on a 

 horizontal axis, and carrying, half-way up, a cross-bar of soft 



* " Museum of Science and Art," vol. iii. p. 117. 



