26 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 'jG 



the Alliance Company, which had been originally designed in 1850 

 by Nollet, a professor of Physics in the Military School in Brussels. 

 Nollet's original design was of a dynamo having several rows of per- 

 manent magnets mounted radially on a stationary frame, with an 

 equal number of bobJMns mounted on a shaft which rotated and had a 

 commutator so direct current could be obtained. A company was 

 formed to sell hydrogen gas for illuminating purposes, the gas to be 

 made by the decomposition of water with current from this machine. 



Alliance Dynamo, 1862. 



This was the dynamo used in the first commercial installation of an 

 arc hght in the Dungeness Lighthouse, England, 1862. 



Nollet died and the company failed, but it was reorganized as the 

 Alliance Company a few years later to exploit the arc lamp. 



About the only change made in the dynamo was to substitute col- 

 lector rings for the commutator to overcome the difficulties of commu- 

 tation. Alternating current was therefore generated in this first 

 commercial machine. It had a capacity for but one arc light, which 

 probably consumed less than ten amperes at about 45 volts, hence 

 delivered in the present terminology not over 450 watts or about 

 two-thirds of a horsepower. As the bobbins of the armature un- 

 doubtedly had a considerable resistance, the machine had an efficiency 

 of not over 50 per cent and therefore required at least one and a 

 quarter horsepower to drive it. 



