The Rev. N. J. Callan on a new Galvanic Battery. 473 



Figiiies 1 and 2 represent a zinc jilate and a 

 copper cell along with the wires soldered to 

 them. The 20 cojiper cells are put into 

 n wooden box about 3^ feet long, 2 feet 2 

 inches deep, and nearly 3 feet wide, and 

 are separatetl from each other by partitions 

 of wood. The 20 zinc plates are let down 

 into the copper cells, and are lifted up, at Fig. 2. 



pleasure, by means of a windlass. To pre- ^ jpj 



vent the contact of the zinc plates with the 

 copper cells, each zinc plate is covered with 

 a woven net of hemp. When the 20 copper 

 cells are in the wooden box, and the 20 zinc 

 plates in the copper cells, the wires soldered 

 to the copper cells project about f of an inch 



from one of the sides of the box, and their extremities descend 

 nearly 2 inches below the upper edge of the same side: but 

 the wires soldered to the zinc plates project nearly 2 inches 

 from the same side of the box, and their extremities descend 

 as low as the extremities of the wires belonging to the copper 

 cells. Thus, if A B (fig. 3.) in the exterior surface of one of 



Fig. 3. 

 A B 



the sides of the box be parallel to the upper edge of the same 

 side, and nearly 2 inches below it, then the row of points c c' 

 will represent the extremities of the wires belonging to the 

 copper cells, and the row of points z z' will represent the ex- 

 tremities of the wires soldered to the zinc plates. 



The acid solution is poured into the copper cells, which are 

 water-tight, and is let out, without lifting the cells, by means 

 of a cock at the bottom of each cell. The cells are barely 

 wide enough to allow the free ascent and descent of the zinc 

 plates. About 30 gallons of fluid are required to charge the 

 whole battery. Both sides of each zinc plate are exposed to 

 the action of the acid mixture, and are within about a quarter 

 of an inch of an equal and parallel surface of copper. Hence 

 the acting surface in each plate is 8 square feet, and the acting 

 surface of zinc as well as of copper in the whole battery is 160 

 square feet. 



By eight mercury troughs, metallic co'.nmunications may be 

 formed between the 20 zinc plates and the copper cells, so as 

 to make the whole act as a single pair of plates, each containing 

 160 square feet of surface ; or as 2 voltaic circles, in which 



Third Series. Vol.9. No, 56. Dec. 1836. 3L 



