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G.—ENGINEERING. 187 
electricity for the purpose, and distances up to four miles were tried. 
In 1774 Lesage of Geneva proposed 26 wires in earthenware pipes with pairs 
of pith-balls at the end of each wire, which flew apart when the conductor 
of a frictional machine was brought near the other end of the wire. A 
current of electricity was unknown until Galvani’s discovery in 1789, and 
Volta’s pile was first constructed in 1792. Carlisle in 1800 found that 
water was decomposed by passing the current from a Volta pile through 
it, and this was the basis of the telegraph proposed by S6mmering in 1809, 
in which 26 wires ended in 26 metallic points arranged in a row along the 
bottom of a kind of aquarium. By means of a lettered keyboard at the 
sending end the current could be applied to any wire, and a stream of 
bubbles caused to rise from the appropriate point, each point being duly 
labelled with its appropriate letter. The magnetic effect of the electric 
current was discovered in 1819, and immediately replaced the previous 
methods in efforts to develop an electric telegraph ; except for the attempts 
to make a high-speed chemical telegraph, all subsequent telegraph systems 
have employed the magnetic effect of the current. A great many of the 
fundamental inventions of telegraphy were made in the thirties ;_ the list 
includes the needle instrument of Cooke and Wheatstone, the sounder of 
Henry, the dot-and-dash inker of Morse, and the use of the earth as a return 
by Steinheil. Although the needle instrument is now obsolete, the sounder 
and Morse inker are stillcommonly employed. Many have been the devices 
for increasing the amount of traffic which can be worked over a single line, 
either by the simultaneous use of the line by a number of operators, as 
in the quadruplex and multiplex systems, or by punching the messages on 
paper tapes, which can then be fed into an automatic transmitter working 
at a speed ten to twenty times that attainable by a manual operator. In 
the most up-to-date systems the perforation of the tape is done by the 
operators working an ordinary typewriter keyboard, and the received 
_ message is printed in ordinary type, a single wire carrying eight messages 
- simultaneously, four in either direction, at a speed of 40 words per minute. 
The need for telegraphic communication between countries separated 
_ by water was so much the greater because of the slowness of other means of 
communication, but the difficulties in laying and maintaining 2,000 miles 
= 
of insulated wire on the bottom of the sea must have appeared almost 
insuperable to the early workers; fortunately, however, there were men 
who had the necessary vision and courage. The flimsiness of the early 
cables suggests that the pioneers underestimated the magnitude of the 
problem which faced them, which was perhaps fortunate. A cable was 
laid between Dover and Calais in 1850 ; it lived only a single day, but it 
_ was replaced in the following year by a successful cable. 
The first cable was laid across the Atlantic in 1858, and, although in 
_ the light of our present knowledge we know that it could not have had a 
_ very long life, its failure after a few weeks of preliminary communication 
was primarily due to misuse owing to the ignorance of those in charge. 
Although much costly experience had been gained in the laying of cables 
various parts of the world since this first attempt to span the Atlantic, 
success of the second Atlantic cable in 1866 was largely due to the 
tt ability of Kelvin and to his enthusiastic and untiring application 
to the project at every stage of the manufacture and laying of the cable. 
In addition to this, he not only designed the receiving instruments, but 
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