NATURE AND STRENGTH OF THE BATTERY ACID. 269 



and the more accurate and philosophical mode of estimating the results by the equi- 

 valents of zinc consumed, will be their sufficient justification. 



1137. Nature and strength of the acid. — My battery of forty pairs of three-inch 

 plates was charged with acid consisting of 200 parts water and 9 oil of vitriol. Each 

 plate lost, in the average of the experiments, 4-66 equivalents, or the whole battery 

 186-4 equivalents, of zinc, for the equivalent of water decomposed in the volta-elec- 

 trometer. Being charged with a mixture of 200 water and 16 of the muriatic acid, 

 each plate lost 3'8, or the whole battery 152, equivalents of zinc for the water de- 

 composed. Being charged with a mixture of 200 water and 8 nitric acid, each plate 

 lost 1-85, or the whole battery 74*16, equivalents of zinc for one equivalent of water 

 decomposed. The sulphuric and muriatic acids evolved much hydrogen at the plates 

 in the trough ; the nitric acid no gas whatever. The relative strengths of the original 

 acids have already been given (11 27.); but a difference in that respect makes no 

 important difference in the results when thus expressed by equivalents (1140.). 



1138. Thus nitric acid proves to be the best for this purpose : its superiority ap- 

 pears to depend upon its favouring the electrolization of the liquid in the cells of the 

 trough upon the principles already explained (905. 973. 1022.), and consequently 

 favouring the transmission of the electricity, and therefore the production of transfer- 

 able power (1120.). 



1139. The addition of nitric acid might, consequently, be expected to improve sul- 

 phuric and muriatic acids. Accordingly, when the same trough was charged with a 

 mixture of 200 water, 9 oil of vitriol, and 4 nitric acid, the consumption of zinc was 

 at each plate 2786, and for the whole battery 111-5, equivalents. When the charge 

 was 200 water, 9 oil of vitriol, and 8 nitric acid, the loss per plate was 2-26, or for the 

 whole battery 90-4, equivalents. When the trough was charged with a mixture of 

 200 water, 16 muriatic acid, and 6 nitric acid, the loss per plate was 2-11, or for the 

 whole battery 84-4, equivalents. Similar results were obtained with my battei-y of 

 twenty pairs of four-inch plates (1129.). Hence it is evident that the nitric acid was 

 of great service when mingled with the sulphuric acid ; and the charge generally 

 used after this time for ordinary experiments consisted of 200 water, 4 J oil of vitriol, 

 and 4 nitric acid. 



1140. It is not to be supposed that the different strengths of the acids produced 

 the differences above ; for within certain limits I found the electrolytic effects to be 

 nearly as the strengths of the acids, so as to leave the expression of force, when given 

 m equivalents, nearly constant. Thus, when the trough was charged with a mixture 

 of 200 water and 8 nitric acid, each plate lost 1-854 equivalent of zinc. When the 

 charge was 200 water and 16 nitric acid, the loss per plate was 1-82 equivalent. 

 When it was 200 water and 32 nitric acid, the loss was 2-1 equivalents. The differ- 

 ences here are not greater than happen from unavoidable irregularities, depending 01^ 

 other causes than the strength of acid. ..; 



1141. Again, when a charge consisting of 200 water, 4 J oil of vitriol, and 4 nit/i^ 



