DYNAMO-ELECTRIC MACHINE. 331 



thereby practically solved, was the construction of an 

 effective electric exploding apparatus without steel 

 magnets, and such exploding apparatus is still in general 

 use at the present day. The Berlin physicists, among 

 them Magnus, Dove, Riess, du Bois-Reymond , were 

 extremely surprised, when I laid before them in 

 December 1866 such an exploding inductor, and 

 showed, that a small electro-magnetic machine without 

 battery and permanent magnets, which could be turned 

 in one direction without effort and with any velocity, 

 offered an almost insuperable resistance when turned 

 in the opposite direction, and at the same time produced 

 an electric current of such strength, that its wire -coils 

 became quickly heated. Professor Magnus immediately 

 offered to lay a description of my invention before 

 the Berlin Academy of Sciences, but, on account of 

 the Christmas holidays, this could only be done in the 

 following year, on the 17 th of January 1867. 



The priority of my application of the dynamo- 

 electric principle was afterwards impugned in various 

 quarters, when its enormous importance came to be 

 seen in its further development. At first, Professor 

 Wheatstone was almost universally recognised in Eng- 

 land as simultaneous inventor, because at a sitting of 

 the Royal Society on the 15 th of February 1867, at 

 which my brother William produced my apparatus, he 

 immediately exhibited a similar apparatus, which was 

 only distinguishable from mine by the wire -coils of 

 the fixed electro-magnet being differently disposed in 

 their relation to those of the rotating cylindrical magnet. 



