127 



potassa, in the first five minutes, 0. 8 of a cubic inch of 

 gases ; in the next five, 0. 25. It was recharged, and gave, in the 

 first five, 1. 0. The plates vt^ere then raised for 5 more, and, in 

 the next five, it gave 0. 45 ; but, had the gas not been al- 

 lowed time to escape from the fluid in the cells, it would have 

 afforded only 0. 3, and the hydrogen would have diminished the 

 effect i. 



For the same reason we do not find, that we gain a proportional 

 augmentation of power by increasing the strength of the acid mix- 

 ture. With ^ of hydrochloric acid, I obtained 0. 8 ; with ^, 

 0. 875 ; and with -■-, 1. 0, where the numbers proportional to the 

 quantities of acid are 8, 9. 3, and 11. 2, Experiments have been 

 made by me on constructing batteries of large surface ; but I have 

 not obtained any striking results. Where the trough is large, 

 much difficulty is usually experienced in making it water-tight ; but 

 the form which I used is very convenient. A cell is formed of thin 

 copper soldered, so as to hold the acid ; from the middle of one of its 

 broad sides proceeds a slip of copper, which is connected with a 

 zinc plate, supported in a similar adjacent cell, so as not to be in 

 contact with its sides. (See the Plate.) The series in this way 

 may be continued ad libitum ; and, from the double surfaces, which 

 are effective in tiiis construction, the aiTangement is extremely pow- 

 erful. In the same plate is exhibited another arrangement, which 

 I have found convenient : its construction is obvious, without 

 any description. I endeavoured, though without success, to ob- 

 tain both quantity and intensity of electricity without tlie enor- 

 mous expence of a series of large plates. It seemed possible, 

 that, as the intensity depended on the number, and the quantity on 

 the size, if the central plates were small, and their magnitude 

 gradually augmented to the extremes, this result might be obtained. 



