205 



AltliouKli considerable work has been done, it lias been entirely of a 

 preliniinary character. With a magnet of pole-strength 415, making 4,000 

 revolutions per minute, witli IdO copper wires (w) and 100 German silver 

 wires (wM. the junior author of this pnpcr found that no current was 

 indicated by a galvanometer whose constant was 1.1x10-''. The magnet 

 was rotated by an electric motor and the galvanometer was placed on a 

 pier in an ad.ioiniug room some thirty feet distant. Work with electro- 

 lytes is now in progress. 



The senior author is arranging to make the apparatus more sensitive 

 liy using an electromagnetic field and a more delicate galvanometer. 

 Results will be given in a future paper. 



