PHILOSOPHICAL SOCIETY OF WASHINGTON. 47 



results of some investigations carried on independently in this 

 country by Mr. J. A. Maloney and Mr. Franz Burger, of Wash- 

 ington, and afterward by himself in connection with them. 



Mr. Maloney and Mr. Burger had been aiming to interpose in 

 the circuit of the electric lamp a reservoir of energy which should 

 perform the same function for the electric lamp that a gasometer 

 .did for a gas-burner, viz., prevent its nickering by keeping a con- 

 stant or nearly constant potential on the main line, even though the 

 current from the source should be irregular. 



A long course of experiment convinced them that plates of lead 

 immersed in dilute sulphuric acid form a combination preferable to 

 any other for giving return currents when once these plates have 

 been made part of an electric circuit. They noticed what they 

 believed to be an oxide of lead formed on one plate, and since the 

 thicker the coating of oxide the greater the effect, they began to 

 regard this layer as a sort of sponge which, in some way, held the 

 electricity, and they concluded to increase the holding capacity of 

 the cell by increasing the thickness of the sponge. Oxide of lead 

 was accordingly purchased and painted on, with results which were 

 surprising. The storage of electricity in large quantity was effected. 

 This was of course independent and without any knowledge of Mr. 

 Faure's work in Europe, but the chief merit of their inquiry lies in 

 the rapidity with which they grasped the idea of mechanically in- 

 creasing the sponge-like coating. 



While they were testing the capabilities of the battery and were 

 still endeavoring to improve it, the announcement was made of Mr* 

 Faure's similar inventions. Soon after the battery was submitted 

 for experiment to three members of this Society, and subsequently 

 the co-operation of the author was invited for further study of the 

 subject. 



On examining the plates during their summer investigations they 

 found reason for believing that the published theory of the action 

 of the cell was but partly correct; for after the plates had been 

 charged the changes of color and, therefore, of chemical constitu- 

 tion, upon which the return current was supposed to depend, were 

 found, in general, not to take place until the return current had 

 been passing for some time. If so, in something else than chemical 

 combination must lie the storage capacity of these cells. The con- 

 clusion arrived at from their investigations was that the change of 



