104 PROCEEDINGS OF THE REGENTS 



ledge would have attempted to use it in that connexion after reading 

 my paper. 



In sending a message to a distance two circuits are employed, the 

 first a long circuit through which the electricity is sent to the distant 

 station to bring into action the second, a short one, in which is the 

 local battery and magnet for working the machine. In order to give 

 projectile force sufficient to send the power to a distance, it is neces- 

 sary to use an intensity battery in the long circuit, and in connexion 

 with this, at the distant station, a magnet surrounded with many 

 turns of one long wire must be employed to receive and multiply the 

 efiect of the current enfeebled by its transmission through the long 

 conductor. In the local or short circuit either an intensity or a quan- 

 tity magnet may be employed. If the fi.rst be used^ then with it a 

 compound battery will be required ; and, therefore, on account of the 

 increased resistance due to the greater quantity of acid, a less amount 

 of work will be performed by a given amount of material ; and, con- 

 sequently, though this arrangement is practicable it is by no means 

 economical. In my original paper I state that the advantages of a 

 greater conducting power, from using several wires in the quantity 

 magnet, may, in a less degree, be obtained by substituting for them one 

 large wire ; but in this case, on account of the greater obliquity of 

 the spires and other causes, the magnetic effect would be less. In 

 accordance with these principles, the receiving magnet, or that which 

 is introduced into the long circuit, consists of a horse-shoe magnet 

 surrounded with many hundred turns of a single long wire, and is 

 operated with a battery of from 12 to 24 elements or more, while in 

 the local circuit it is customary to employ a battery of one or two 

 elements with a much thicker wire and fewer turns. 



It will, I think, be evident to the impartial reader that these were 

 improvements in the electro-magnet which first rendered it adequate 

 to the transmission of mechanical power to a distance ; and had I 

 omitted all allusion to the telegraph in my paper, the conscientious 

 historian of science would have awarded me some credit, however 

 small might have been the advance which I made. Arago and Stur- 

 geon, in the accounts of their experiments, make no mention of the tel- 

 egraph, and yet their names always have been and will be associated 

 with the invention. I briefly, however, called attention to the fact of 

 the ap[)licability of my experiments to the construction of the tele- 

 graph ; but not being familiar with the history of the attempts made 

 in regard to this invention, I called it "Barlow's project," while I ought 

 to have stated that Mr. Barlow's investigation merely tended to dis- 

 prove the possibility of a telegraph. 



