CONSIDERATIONS ON ELECTRICITY. 317 



which originate under other circumstances. Thus, for example, from nitric acid 

 proceed many products of decomposition which are set free in the acid and weaken 

 its capacity for the absorption of liydrogen. The action ceases perhaps jnly in 

 consequence of the excessive resistance which the depoLarizing ]i(]nid s(> quickly 

 assimies. This cessation supei-venes more speedily with the combinations of 

 oxygen heretofore tried; besides that they are very costly and yield residuums 

 which are of no value. Batteries of this order are generally very intense for a 

 certain number of hours, but their intensity then diminishes very rapidly, for the 

 twofold reason already mentioned. The metallic salts, which exert scarcely any 

 influence on the acting liquid, better preserve their intensity. Since they are\-ead- 

 ily reduced, it is only their conductibility which comes into consideration. As the 

 inmiersed electrode is of the same nature, it will for some time be improved at 

 the expense of the salt, and in consequence of this reaction will also maintain 

 the physical uniformity in its vicinity. 



Any advice respecting the diaphrams must necessarily be very precarious ; 

 they are detrimental through the resistance which they occasion and on account 

 of the want of identity in their constitution. 



The inventor of an electrical battery has still to pay attention to the con- 

 ductibility. It must be here remembered that the chemical decompositions pro- 

 ceed in fixed proportions, and since, as soon as the current circulates, each pair 

 in a battery acts as a decomposing apparatus, and each performs the same labor, 

 it suffices to detennine the performance of but one pair in order to be able to 

 compute that of the whole battery. TZie weight of the copper precipitated in a 

 voltameter is directly proportional to the electro-motive force of the pair, and is 

 in inverse proportion to the resistance. As, according to the electro-chemical 

 law, for one equivalent of the precipitated copper, one equivalent of zinc and a 

 con-esponding quantity of the acid are consumed, we have the means of ascer- 

 taining the cost at which the pair operates. In reality, however, this is greater 

 than the theoretical estimate. 



