244 SCIENTIFIC RECREATIONS 



1797, and Wheatstone, in 1840, declared that it was quite possible to 

 connect England and France by wire. Morse and Calt experimented with 

 submarine cables in America, and Lieutenant Siemens first applied gutta- 

 percha to the wires as avi insulator in the Prussian line of telegraph across 

 the Rhine. The English laid a wire between Dover and Calais, which was 

 broken, but successfully relaid. And so on, till in 1857 the great project of 

 the Atlantic cable was broached. We give illustrations of the cables ; the 

 circumstances connected with the laying of which, and the enthusiasm over the 

 successful accomplishment of the task, must be in the memory of all. The 

 readings of the messages were shown by delicate galvanometers, the beam 

 of light being reflected from a mirror. This cable was lost, and in 1862 

 Mr. Field came over to urge the importance of the submarine cable between 

 this country and America. The cable was shipped on the Great Eastern 

 in 1865, and was 2,186 miles long. It consisted of seven copper wires 

 twisted, and covered with gutta-percha. The outside coating consists of ten 

 iron wires surrounded by manilla yarn. But this cable broke, and a third 

 was made and laid in 1866. The old cable was then recovered and spliced. 

 There are some two hundred cables now in existence, the last being the Cape 

 cable, laid when the Boer War was engaging our attention. The transmitting 

 apparatus of Mr. Varley and Sir W. Thomson has greatly accelerated the 

 rapidity of messages, and Thomson's syphon recorder farther increased the 

 speed. 



The following description of a new system is from Scribner*s Magazine 

 for 1880 : 



"NEW TELEGRAPHIC SYSTEM. 



*' A new system of sending and receiving electrical impulses over an 

 insulated wire has recently been brought into successful operation, that 

 seems to promise not only a radical change in the present methods of tele- 

 graphing, but a material gain in the speed and cost of sending messages by 

 wire. It is founded on a union of the so-called "automatic" and "chemical" 

 systems of telegraphy. The first of these employs a strip of paper having, 

 by some mechanical means, a series of small holes punched in it, the design 

 being to pass the perforated strip under a needle, or stylus, in electrical 

 connection with the line. This stylus, on passing over the paper, opens the 

 circuit, but in passing one of the holes, drops through and closes it, this 

 alternate making and breaking of the circuit transmitting the message. The 

 chemical telegraph records any electrical impulses sent over a line by staining 

 a strip of prepared paper passing under it. This is founded on the fact 

 that electricity has the power of decomposing certain chemicals, and if paper 

 is soaked in these chemicals and submitted to the action of electricity, it will 

 be discoloured wherever the current passes. While both of these systems 

 have been used, neither has been able to compete with the more simple 

 Morse key and sounder, and it has remained for the new system to bring 

 them to a position where they may come into general use. The new system 



