96 On the Decomposition of Water by the Galvanic Battery. 



that a deflection of 22§° was produced in the needle of the sine 

 galvanometer. But I am inclined to think that had I made the 

 experiment the day I used the 40 cellsj the deflection would 

 have been considerably less, because the needle was not then so 

 highly magnetized. The impression made by all my experiments 

 inclines me to believe that a battery would work nearly twice as 

 long in decomposing water as in igniting coke points; that, 

 therefore, the coke light and the lime light are nearly equally 

 expensive, but that the former is somewhat more ceconomical. 

 I shall soon have occasion to exhibit a battery of about 250 cast- 

 iron cells, and intend then to compare the quantity of electricity 

 which will pass between a pair of coke points ignited by 40 

 cells, with that which will pass through a thick wire connected 

 with the opposite ends of the same 40 cells. I intended to 

 investigate the decomposing power of the coil, but I must defer 

 the investigation till health and leisure permit me to resume 

 my experiments. 



Maynooth College, 

 January 2, 1854. 



P.S. I have got a new iron vessel made of a rectangular form, 

 for which I am preparing two sets of electrodes ; one for a battery 

 of low intensity, the other for a battery of high intensity. The 

 former will consist of 100 iron plates coated with an alloy of lead 

 and tin ; 50 of them (the alternate plates) will be connected with 

 one end of the battery, and the other 50 with the opposite end. 

 The 100 plates will be divided into twenty groups, each contain- 

 ing 5 plates. Each group will be covered all round with linen, 

 so that the foam produced by the ascent of the gases in the solu- 

 tion of soda may be made to pass through the linen, and that 

 thus the bubbles may be broken. This arrangement of the elec- 

 trodes will answer for a battery of 60 cast-iron cells arranged in 

 fifteen rows of four each, and in which each zinc plate is 6 inches 

 by 4. The quantity of the gases produced by each group of 5 

 plates will be equal to that which would be produced by 3 cast- 

 iron cells, or the gu^^ ^^ ^^' Now I have found that a linen 

 cover on the electrodes prevents all foam when the battery does 

 not contain more than 5 or 6 cells, in which each zinc plate is 

 6 inches by 4. Therefore in the arrangement just described 

 there can be no foam. The electrodes for a battery of high in- 

 tensity will consist of 156 coated iron plates, divided into twelve 

 groups each containing 13 plates. The 13 plates of each group 

 will form 12 decomposing cells nearly water-tight, and open only 

 at the top. The first plate of each group will be connected with 

 one end of the battery, and the last with the opposite end. 

 Hence when the cells are nearly filled with a solution of soda, 



