474 



concentrated acids, or by the solution of nitre. The battery 

 was kept working for nearly an hour. During that time there 

 was very little diminution of its power, and apparently no ac- 

 tion on the lead or platina powder. 



" I afterwards tried the power of Ihe leaden battery when 

 the lead was excited first by the nitre dissolved in water with- 

 out acid, and then by the diluted sulphuric acid without nitre. 

 The voltaic current was feeble in both cases. When a few 

 crystals of nitre were put into the cell containing the diluted 

 sulphuric acid, the power of the battery increased as the nitre 

 was dissolved. The power, then, must be ascribed to both : 

 to the nitre and sulphuric acid. 



" I have compared the power of platinized or gilded lead, 

 excited by dilute sulphuric acid, with that of platinized silver, 

 and have found the former fully equal to, and as constant as 

 the latter. 



" From the experiments which have been described, I in- 

 fer, first, that a battery equal in power to that of Professor 

 Grove may be made by exciting platina with a solution of 

 nitre in dilute sulphuric acid, or by exciting gilded or plati- 

 nized lead with concentrated nitro-sulphuric acid, or with 

 common nitre dissolved in sulphuric acid diluted with about 

 an equal bulkof water ; secondly, that platinized or gilded lead 

 may be substituted for platinized silver in Smee's battery. 



" The advantages of what I may call the nitre platina 

 battery over Professor Grove's nitric acid battery, are, first, 

 that the expense of the nitre necessary for working the former 

 for a given time, is only about the thirtieth part of the cost of 

 the nitric acid required to work the latter: the diminution of 

 expense in working the voltaic battery will contribute very 

 much to make electro-magnetism a more economical prime 

 mover than steam ; secondly, that from the nitre battery there 

 are no noxious or disagreeable fumes. 



" The advantages of the nitre leaden battery over Pro- 

 fessor Grove's platina battery, are, first, that the former is 



