DYNAMO-ELECTRIC MACHINE. 333 



force in the space allotted to my firm, and the jury, 

 to which I myself belonged, did not subject the exhibits 

 of their members, which were "hors concours", to any 

 trial. All the greater was the sensation caused by 

 an imitation of my machine exhibited by an English 

 mechanician, which produced from time to time a small 

 electric light. It was considered a sufficient recognition 

 that the order of the Legion of Honour was awarded 

 to me at the close of the exhibition. 



When at a later time the dynamo-machine, after 

 considerable improvement, especially by the introduction 

 of Pacinottrs ring and Hefner's coiling system, had 

 received the most extensive application in practice, 

 and both mathematicians and engineers had developed its 

 theory, it seemed almost self-evident and hardly to be 

 called an invention, that one should arrive by merely 

 reversing the rotation of an electro-magnetic machine 

 at the dynamo -electric machine. Against this it may 

 be said, that the most obvious inventions, of primary 

 importance, are commonly made very late, and in the 

 most round-about way. For the rest it would not 

 have been easy to have arrived by accident at the 

 discovery of the dynamo-electric principle, because 

 electro-magnetic machines only "excite", i. e. spon- 

 taneously strengthen their electro-magnetism on re- 

 versing the rotation, when their dimensions and the 

 disposition of the coils are perfectly correct. 



To this period also belongs my invention of 

 the alcoholmeter, which very successfully solved an 

 extremely difficult problem, and accordingly excited 



