18730 



Magneto-Electric Illumination. 



309 



the two contrary currents produced simultaneously in the 

 wire surrounding the electro-magnet, we have only to 

 connect the wires at the mean position to two conductors 

 by friction contacts, F f', when the current can be carried 

 away to a galvanometer, G, and rendered sensible. 



Fig. 1. 



The principle of the arrangement being thus understood, 

 the construction of the machine itself will be readily in- 

 telligible. 



It consists of a permanent horse-shoe magnet, s, o, n, 

 Fig. 3, between the poles of which revolves an electro- 

 magnet. This electro- magnet consists of a ring of soft 

 iron, round which is wound an insulated conducting wire, 

 presenting no solution of continuity. It may be conceived 

 as being an ordinary straight electro-magnet bent round in 



Fig. 2. 



a circle, and the two ends of the conducting wire soldered 

 together to establish continuity. 



In Figs. 4 and 7 the electro-magnet is represented at A in 

 section, whilst in Figs. 3 and 5 it is shown at A with the 

 covering wire on it. It revolves round its axis on an axle to 

 which movement is communicated either by means of 



vol. in. (n.s.) 2 s 



