476 
dilute nitro-sulphuric acid and nitre, produces a more powerful 
voltaic current than platina does when excited by nitric and 
sulphuric acid. In consequence of the small quantity of acid 
contained in the lead cell, its power declined sooner than that 
of the platina. From the results of several experiments made 
with the platina and lead batteries, I have come to the con- 
clusion that the expense of doing a given amount of work by 
the former, excited by nitric and sulphuric acid, would be 
about three times as great as if the work were done by the 
latter, excited by a mixture of nitre and sulphuric acid. 1 have 
tried a mixture containing one part of sulphuric acid and three 
parts of water, in which a little sulphate of soda and nitre was 
dissolved. When the platinized lead was excited by this mix- 
ture, the power of the battery was very great, but not so great 
as when the mixture contained as much sulphuric acid as 
water. I have not as yet tried any other sulphate as a sub- 
stitute for the sulphuric acid. When the platinized or gilded 
lead is taken out of the cell, it should be rinsed in water, and 
dipped into a weak solution of chloride of gold or platina. By 
this means, and by amalgamating the lead plates with mer- 
cury, before they are gilded or platinized, the platina or gold 
powder may be kept on them for a long time. 
‘‘ The reason why the platinized or gilded lead produces so 
powerful a voltaic current is, that the acting metals are not lead 
and zine, but platina or gold powder and zine. It appears to 
me that the current produce by zine and platina, or gold 
powder, is more powerful than that which is produced by zine 
and platina, or gold. Perhaps by depositing on lead a powder 
of some of the metals, such as tungsten, arsenic, &c., which 
are More negative, compared with zinc, than platina or gold 
is, a battery may be yet made which will be more powerful 
than the platina or platinized lead battery. I have tried an- 
” 
. 
timony, but it did not answer 
