NITRIC ACID BATTERY. 233 



acids. It now occurred to me that as gold, platina, and two 

 acids gave so powerful an electric current, a fortiori, the same 

 arrangement, with the substitution of zinc for gold, must form 

 a combination more energetic than any yet known. I delayed 

 not to submit this to experiment, and was gratified with the 

 most complete success. A single pair, composed of a strip of 

 amalgamated zinc an inch long and a quarter of an inch 

 wide, a cylinder of platina three-quarters of an inch high, with 

 a tobacco-pipe bowl and an egg-cup, readily decomposed 

 water acidulated with sulphuric acid. In this battery the 

 action is constant, and there is no precipitation on either 

 metal. It offers the great advantage of being able to utilise 

 the action of concentrated nitric acid. I tried the same 

 arrangement, substituting for the muriatic acid caustic potass, 

 which was suggested to me by a well-known experiment of 

 M. Becquerel : the action was equally powerful ; and I should 

 prefer this arrangement, as there is no necessity for amalga- 

 mating the zinc, but for a fatal objection the nitrate of potass, 

 crystallising in the pores of the earthenware, splits it to 

 pieces ; except, therefore, a new description of diaphragm be 

 discovered, which will bear the action of powerful acids, this 

 combination must be abandoned. 



I diluted the muriatic acid with twice its volume of water, 

 and the effect was not perceptibly inferior. I then tried sul- 

 phuric with four or five times its volume of water ; the intensity 

 was a little diminished, but so little that I should prefer this 

 combination to any other, as cheaper, exercising less local 

 action on the zinc, and by no possibility endangering the pla- 

 tina. The nitric acid may be the common acid of commerce, 

 but must be concentrated. If the hydrogen, instead of being 

 absorbed by the oxygen of the nitric acid, is evolved on 

 the surface of the platina, the energy of action is lowered and 

 is no longer constant. 



Great advantage will be found in employing a cell divided 

 by a porous diaphragm for a decomposing cell ; thus, if oxygen 

 gas be wanted, the positive electrode should be put into dilute 

 sulphuric acid and the negative into concentrated nitric. If 

 chlorine be wanted, the positive into muriatic, the negative 

 into nitric ; if hydrogen, both into muriatic ; the positive one 



