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qiiantitrj magnets were introduced to avoid circumlocution, and were 

 intended to be used merely in a technical sense. By ih.e intensity magnei 

 I designated a piece of soft iron, so surrounded with wire that its magnetic 

 power could be called into operation by an intensity battery, and by a 

 quantify magnet, a piece of iron so surrounded by a number of separate 

 coils, that its magnetism could be fully developed by a quantity hatter j. 



I was the first to point out this connection of the two kinds of the bat- 

 tery with the two forms of the magnet, in my paper in Silliman's Journal 

 January, 1831, and clearly to state that when magnetism was to be devel- 

 oped by means of a compound battery, one long coil was to be employed, 

 and when the maximum effect was to be produced by a single battery, a 

 number of single strands were to be used. 



These steps in the advance of electro-magnetism, though small, were 

 such as to interest and astonish the scientific world. With the same bat- 

 tery used by Mr. Sturgeon, at least a hundred times more magnetism was 

 produced than could have been obtained by his experiment. The devel- 

 opments were considered at the time of much importance in a scientific 

 point of view, and they subsequently furnished the means by which mag- 

 neto-electricity, the phenomena of dia-magnetism, and the magnetic effects 

 on polarized light were discovered. They gave rise to the various forms 

 of electro-magnetic machines which have smce exercised the ingenuity of 

 inventors in every part of the world, and were of immediate applicability 

 in the introduction of the magnet to telegraphic purposes. Neither the 

 electro-magnet of Sturgeon nor any electro-magnet ever made previous to 

 my investigations was applicable to transmitting power to a distance. 



The principles I have developed were properly appreciated by the 

 scientific mind of Dr. Gale, and applied by him to operate Mr. Morse's 

 machine at a distance. 



Previous to my investigations the means of developing magnetism in 

 soft iron were imperfectly understood. The electro-magnet made by 

 Sturgeon, and copied by Dana, of New York, was an imperfect quantity 

 magnet, the feeble power of which was developed by a single battery. 

 It was entirely inapplicable to a long circuit with an intensity battery, 

 and no person possessing the requisite scientific knowledge, would have 

 attempted to use it in that connection 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 projec- 

 tile force sufficient to send the power to a distance, it is necessary to uso 

 an intensity battery in the long circuit, and in connection with this, at 

 the distant station, a magnet surrounded with many turns of one long 



