

ON SOME MARVELS IN TELEGRAPHY. 237 



Although the employment of electricity as a means of 

 communicating at a distance was suggested before the end 

 of the last century, in fact, so far back as 1774, the idea 

 has only been worked out during the last forty-two years. It 

 is curious indeed to note that until the middle of the present 

 century the word "telegraph," which is now always under- 

 stood as equivalent to electric telegraph, unless the contrary 

 is expressed, was commonly understood to refer to sema- 

 phore signalling,* unless the word "electric" were added. 



The general principle underlying all systems of tele- 

 graphic communication by electricity is very commonly 

 misunderstood. The idea seems to prevail that electricity 

 can be sent out along a wire to any place were some suitable 

 arrangement has been made to receive it In one sense 

 this is correct But the fact that the electricity has to make 

 a circuit, returning to the place from which it is transmitted, 

 seems not generally understood. Yet, unless this is under- 

 stood, the principle, even the possibility, of electric com- 

 munication is not recognized. 



Let us, at the outset, clearly understand the nature of 

 electric communication. 



In a variety of ways, a certain property called electricity 

 can be excited in all bodies, but more readily in some than 

 in others. This property presents itself in two forms, which 

 are called positive and negative electricity, words which we 

 may conveniently use, but which must not be regarded as 

 representing any real knowledge of the distinction between 

 these two kinds of electricity. In fact, let it be remembered 

 throughout, that we do not in the least know what elec- 



* Thus in Christie Johnstone, written in 1853, when Flucker John- 

 stone tells Christie the story of the widow's sorrows, giving it word for 

 word, and even throwing in what dramatists call " the business," he 

 says, "'Here ye'll play your hand like a geraffe.' 'Geraffe?' she 

 says ; ' that's a beast, I'm thinking. ' ' Na ; it's the thing on the hill 

 that makes signals. ' ' Telegraph, ye fulish goloshen ! ' ' Oo, ay, tele- 

 graph ! geraffe 's sunnest said for a'.' " " Playing the hand like a 

 telegraph " would now be as unmeaning as Flucker Johnstone's original 

 description. 



