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galvanic circuit. This consisted in closing the second circuit by the 

 deflection of a needle, so placed that the two ends projecting upwards, of 

 the open circuit, would be united by the contact of the end of the needle 

 when deflected, and on opening or breaking of the circuit so closed by 

 opening the first circuit, and thus interrupting the current, when the 

 needle would resume its ordinary position under the influence of the mag- 

 netism of the earth. I informed him that I had devised another method 

 of producing eflfects somewhat similar. This consisted in opening the 

 circuit of my large quantity magnet at Princeton, when loaded with many 

 hundred pounds weight, by attracting upward a small piece of moveable 

 wire, with a small intensity magnet, connected with a long wire circuit. 

 When the circuit of the large battery was thus broken by an action from 

 a distance, the weights would fall, and great mechanical eff"ect could thus 

 be produced, such as the ringing of church bells at a distance of a hun- 

 dred miles or more, an illustration which I had previously given to my 

 class at Princeton. My impression is strong, that I had explained the 

 precise process to my class before I went to Europe, but testifying now 

 without the opportunity of reference to my notes, I cannot speak posi- 

 tively. I am, however, certain of having mentioned in my lectures every 

 year previously, at Princeton, the project of ringing bells at a distance, 

 by the use of the electro-magnet, and of having frequently illustrated the 

 principle of transmitting power to a distance to my class, by causing in 

 some cases a thousand pounds to fall on the floor, by merely lifting a 

 piece of wire from two cups of mercury closing the circuit. 



The object of Professor Wheatstone, as I understood it, in bringing 

 into action a second circuit, was to provide a remedy for the diminution 

 of force in a long circuit. My object, in the process described by me, 

 was to bring into operation a large quantity magnet, connected with a 

 quantity battery in a local circuit, by means of a small intensity magnet, 

 and an intensity battery at a distance. 



The only other scientific facts of importance to the practical operation 

 of the telegraph not already mentioned, are the discovery by Steinheil, 

 in 1837, in Germany, of the practicability of completing a galvanic cir- 

 cuit, by using the earth for completing the circuit, and the construction 

 of the constant battery in 1836, or about that time, by Professor Daniel!, 

 of King's College, London. I believe that I was the first to repeat the 

 experiments of Steinheil and Daniell in this country. I stretched a wire 

 from my study to my laboratory, through a distance in the air of several 

 hundred yards, and used the earth as a return conductor, with a very 

 minute battery, the negative element of which was a common pin, such ag 

 is used in dress, and the positive element the point of a zinc wire im- 

 mersed in a single drop of acid. With this arrangement, a needle was 

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