- ■ - 'by means rif Galuanism, 2Sl 



ing atcr6unt of some experiments T made, about a year and 

 a half ago, with a Galvanic trough containing fifiv pair of 

 plates four inches square. If you think it worthy of a place 

 in your Philosophical iMas;azine, you will insert it therein. 

 Being desirous of ascertaining whether water would be 

 decomposed or no, if the wires, which were connected with 

 t4"ic ends of the trough, were at a considerable distance from 

 one another, I inserted two short silver wires through corks 

 into the ends of a glass tube 36 inches long, and which was 

 filled with water: the ends of the wires were about 34 inches 

 asunder, which distance was too great for any visible de- 

 composition of the water to take place; \<tt that wire which 

 was connected with the zinc end of the trough., gave a very 

 faint whitish cloud which descended *. With a shorter tube 

 the decomposition of the water commenced when the ends 

 of the wires were at the distance of 18 inches. It then 

 struck me, that if a wire was interposed between the two 

 end wires of the long tube a decomposition might possibly 

 be effected at two places in the tube at the same tnue, and 

 that the quantity of gas evolved would be greater than if it 

 was evolved at only one place. I therefore introduced a 

 piece of iron w-ire between the end wires, in such a manner 

 that its ends came within an inch of them. When a com- 

 munication was made with the trough there was a very 

 copious evolution of gas at both ends of the interposed w'xxa, 

 and at that end wire that was connected with the copper 

 end of the trough ; and a red oxide of iron was formed at 

 one end of the iron wire, while a black oxide was formed 

 at the other. 



To try if any increased effect would take place if there 

 was a greater surface of the wires opposed to one another, 

 I pushed the end wires further into the tube till their ends 

 passed about an inch beyond the ends of the inti-rposed 

 wire: when a communication was made between them and 

 the ends of the trough, a very rapid evolution of oas took 

 place throughout the whole extent of the parts of the wires 

 that were opposed. 



Finding the quantity of gas much increased by this ma- 

 nagement, I introduced a wire into each end of a tube about 

 16 inches long. Each of these wires passed nearly the 

 whole length of the tul^e without touching one another, so 

 that the length of the op])osed parts was 1 ; inches. When 

 these were connected with the trough, there was a very co- 



* Wiiha battery of troughs containing 400 pair of plates 4 inclies square, , 

 (lie cleci'iiiposition took jilace when the wires were witliciiawn to the cuds of 

 {!><: tube. 



R 3 pious 



