OF THE LATE MB. WILLIAM 8TUBG1 65 



In 1836 Mr. Sturgeon communicated a paper to the Royal 

 Society, which, however, being denied insertion in the Philo- 

 sophical Transactions, received publication in the Annals of 

 Electricity, entitled, " Researches in Electro-Dynamics." It 

 contains the description of a machine, in which a coil of wire 

 made to revolve between the poles of a horse-shoe magnet 

 becomes the source of copious electrical currents. Another 

 machine is also described, in which the revolving coil is fur- 

 nished with a core of iron. Magneto-electrical coil machines 

 had been constructed previously, the most celebrated being 

 those of Pixii and Saxton. In these machines the current 

 reciprocated at every half revolution of the coil, or a stronger 

 current being forced in one direction than in another, the 

 difference only could be utilized. Therefore, though able to 

 bit some interesting phenomena, such as the spark and 

 shock, they were almost powerless to produce deflections of 

 the magnetic needle or electro-chemical decompositions. Mr. 

 Sturgeon, by means of a very beautiful arrangement of four 

 semi-wheels, mounted on the axis of his machine, united the 

 entire energies of the opposing currents in one direction. 

 This admirable invention received at his hands a still further 

 improvement, by the introduction of springs pressing against 

 the revolving discs, and the use of oil as a lubricating agent ; 

 mercury, which presents many very serious inconveniences, 

 being thus superseded. In fact, the magneto-electrical machine 

 received from Mr. Sturgeon's hands an improvement even 

 more essential than that which the steam engine received from 

 the genius of Watt, and henceforth it could be employed for 

 telegraphic communication, chemical decomposition, and in 

 short all the purposes for which a voltaic battery is available. 

 An opinion is expressed by Mr. Sturgeon that the magneto- 

 electrical machine thus improved, would ultimately entirely 

 supersede the use of the voltaic battery, and I cannot but 

 concur in it for reasons which I have stated fourteen years 

 ago. The argument is simply this. It has been shown by 

 K 



