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 the 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. 
‘¢ | 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 bulk of 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 nitrie 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 
