606 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



a current of electricity would deflect the magnetic needle ; and 

 this was applied to the transmission of messages, and is the basis 

 now of the English system of telegraphing. About the year 1826, 

 Mr. Harrison Gray Dyer, of Long Island, used a registering appa- 

 ratus, which produced a chemical effect from the spark upon pre- 

 pared* paper, somewhat similar to the plan Bain used afterward. 

 Cook and Wheatstone invented an apparatus, in which they used 

 a double-line alphabet, making the alphabet much more brief by 

 its combinations, and also a temporary and permanent magnet 

 somewhat resembling the plan of Mr. Holcomb. After that came 

 the electro-magnetic telegraph, invented by Professor Morse, or, 

 as others say, by Professor Henry, or perhaps by some other per- 

 son. At any rate Professor Morse made the first practical instru- 

 ment, and being aided by the government in trying the experi- 

 ment, that experiment was the beginning of practically sending 

 messages by the electric telegraph. Then came the House tele- 

 graph, using a type-wheel, printing the message in common ty^e, 

 instead of using the Morse alphabet of dots and strokes. The 

 American system of telegraphing has been far in advance of that 

 of any other country ; one reason for which is the fact that wires 

 are elevated more, and thus the prime current is not induced to 

 leave the wire so rapidly. The Atlantic telegraph should theo- 

 retically have worked ; but the gutta-percha insulation was so 

 defective that the prime current soon found its way to the iron 

 wires, and thus the insulation was destroyed. 



There are two theories of electricity ; the first, that of Ampere 

 and others, that the elementary molecules of matter possess inhe- 

 rent in their substances and inseparable from them, quantities of 

 electric fluid. Those substances that possess negative electricity, 

 such as oxygen and chlorine, are called electro-negatives, and 

 have in practice a tendency to appear at the positive pole of the 

 battery in electric decomposition. The metals, ^ and hydrogen, 

 are electro-positives. The other theory accounts for all the phe- 

 nomena of electricity by physical action, by a certain force set 

 free during chemical action. When we decompose zinc, we set 

 free a positive energy that before was the combining force hold- 

 ing the particles of zinc together in their peculiar position. This 

 force is not a fluid passing through the conducting wire, but acts 

 upon the first particle of matter, that acting upon the second, and 

 that upon the third, and so on through. Mr. Holcomb's method 

 uses a permanent as well as a temporary magnet. Assuming the 



