PROCEEDINGS OF THE EEGENTS, 103 



consequently the number of turns being commensurate with the pro- 

 jectile power of the battery. 



In describing tbe results of my experiments the terms intensiiij and 

 quantity magnets were introduced to avoid circumlocution, and were 

 intended to be used merely in a technical sense. By the intensity 

 magnet 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 quantity magnet, a piece of iron so surrounded by a 

 number of separate coils that its magnetism could be fully developed 

 by a quantity battery. 



I was the first to point out this connexion of the two kinds of 

 the battery with the two forms of the magnet in my paper in Silli- 

 man's Journal, January 1831, and clearly to state that when mag- 

 netism was to be developed by means of a compound battery, one long 

 coil was to be employed, and when the maximum effect was to be pro- 

 duced by a single battery, a number of single strands were to be used. 



These steps in the advance of electro-magnetism though sraall^ were 

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

 ^attery used by Mr. Sturgeon, at least a hundred times more mag- 

 netism was produced than could have been obtained by his experiment. 

 The developments were considered at the time of much importance 

 in a scientific point of view, and they subsequently furnished the means 

 by which magneto-electricity, the phenomena of dia-magnetism, and 

 the magnetic efiects on polarized light were discovered. They gave 

 rise to the various forms of electro-magnetic machines which have 

 since 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 wag 

 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 inten- 

 sity battery, and no person possessing the requisite scientific know- 



