852 Memorandum of Experiments, fyc. COct. 



of a series of rectangular copper cells, (water-tight) fifteen inches 

 square, and the sides three-fourths of an inch apart. To one lip of 

 the cell is soldered a small copper tube a (water-tight) in which a 

 few drops of mercury are contained. One of these cells is shewn 

 in the plate, fig. 1. 



Each copper cell is provided with a sheet of zinc plate, fourteen and 

 a half inches square, to which a thick copper wire, seven inches long, 

 is firmly soldered. Each zinc plate is amalgamated with mercury, 

 and enclosed in a pasteboard case, the construction of which deserves 

 attention, as upon it depends much of the action of the battery. 



Two sheets of brown pasteboard are cut, of such dimensions that 

 they will freely slide into the copper cells. The pasteboards are then 

 placed over each other, and their edges fastened together at three sides 

 by thin slips of teak, half an inch wide, bound together by a few copper 

 screws. A case or bag of this kind when well made is water-tight 

 at the joints, but allows slow filtration to take place through its sides. 

 One of these cases is shewn at fig. 2. 



To arrange each cell the zinc sheet is introduced into the paste- 

 board case, and this into the copper cell. 



Twelve of these cells constitute what we may term one division. 

 The cells must not touch, and are accordingly separated by slips of 

 wood. The zinc sheet from cell No. 1 is connected by its wire with 

 the copper cell No. 2, the zinc of 2 with the copper of 3, and so 

 on, as shewn in fig. 4, in which twelve are placed in a box together. 



To excite the battery two different solutions are employed, one a 

 solution of blue-stone (sulphate of copper, nila tutiya). This salt costs 

 in the Calcutta bazars about twenty-two rupees per maund. 



The second solution is made of sulphate of soda, (Glauber salt, 

 Kari nimuk), dissolved in warm water, and allowed to cool be- 

 fore use. 



Each copper cell is to be filled to two-thirds of its depth with 

 the blue liquid. The pasteboard cases with their zinc sheets are to be 

 steeped in the Glauber salt solution till thoroughly soaked, then slip- 

 ped into the copper cells, and filled up with the same liquid. The 

 battery is then ready for use. 



