2 74 Literary and Philosophical Society. 



testimony to his great scientific merits, and cannot be read 

 without interest : — 



' " My dear Sir, — I have sifted Mr. Sturgeon's claims to 

 the utmost. I have examined all the periodicals likely to 

 throw light upon the history of electro-magnetism, and 

 find that Mr. Sturgeon is, without doubt, the originator of 

 the electro-magnet, as well as the author of the improved 

 electro-magnetic machine. The electro-magnet described 

 by Mr. Sturgeon in the * Transactions of the Society of Arts 

 for 1825 ' is the first piece of apparatus to which the name 

 could with propriety be applied. Arago, and Ampere, and 

 Davy had already, it is true, magnetised steel needles by 

 passing currents of electricity along spirals surrounding them, 

 but it does not appear that they observed the phenomena with 

 iron needles, nor that they had any knowledge of the sud- 

 denness with which the polarity of soft wrought iron might 

 be reversed by a change in the direction of the current. It 

 appears, therefore, quite clear that to Mr. Sturgeon belongs 

 the merit of producing the first electro-magnet constructed 

 of soft iron, as well as that of ascertaining its peculiar and 

 most remarkable properties. Hence it was that M. Jacobi, 

 of St. Petersburg^ claimed for Mr. Sttirgeon, in conjunction 

 ivith Professor CErsted^ the discovery of the electro-magnetic 

 engine. Mr. Sturgeon's claims with regard to the magneto- 

 electrical machine appear to me to be equally well estab- 

 lished. He was the first who devised and executed an 

 apparatus for throwing the opposing currents into one 

 direction, thus accomplishing for this machine exactly what 

 Watt accomplished for the steam engine. Beside this, he 

 is beyond dispute the author of the systems of solid brass 

 discs and insulators, going by the name of ' commutator ' 



