318 Mr. Smee on the Galvanic Properties of Metals, 
of the many metals that I have tried can be used with similar 
good results, except palladium, which though it has not much 
effect in the sponge, is found when precipitated on platinum 
or silver to possess powers, about equal to the finely-divided 
platinum. Precipitated silver increases the power of the me- 
tals, but not nearly to the extent of platinum. 
Having ascertained that a solution of platinum must be 
used for increasing the power of metals in their ordinary 
state, it becomes a matter of great importance to ascertain 
whether the platinum may be precipitated upon other metals 
with advantage ; and for this purpose it was deposited 
upon earthenware, palladium, pure silver, copper plated 
with silver, nickel, German silver, tin, lead, brass, cast iron, 
sheet iron, steel, zinc, and charcoal. The platinized earthen- 
ware was not found to answer, apparently from the quantity 
of the metal not being sufficient to carry the electricity. Pal- 
ladium, silver, and plated silver answered equally well with 
platinum to receive the precipitated metal, and if there was 
any difference, I think the silver was rather the best. Plated 
copper answers very well, but care should be taken to var- 
nish every copper edge, or else that metal is apt to be slightly 
dissolved, and deposited again upon the platinized silver, 
which is injurious. Should copper, from any cause, get upon 
the silver, it may be dissolved by a little muriatic acid, and 
afterwards by a little strong ammonia. No other metal or 
alloy besides this answered for the reception of the platinum, 
except iron, and this was as active as silver for a time, but 
then a local battery was formed between the platinum and 
iron — the iron was dissolved and the battery destroyed. In 
some cases this does not take place so rapidly as in others. 
Carbon answers admirably for the reception of the platinum, 
and is improved in like manner. 
We have now the elements for the manufacture of a power- 
ful battery ; for we have seen that increase of power is ob- 
tained by taking care that the negative metal is thoroughly 
wetted by the fluid, and that this is not only accomplished, 
but its power materially increased by the numerous points 
formed by the precipitation oF finely-divided platinum. What- 
ever metal, alloy, or compound may be found hereafter to 
succeed for the reception of the platinum, or whatever metal 
may be found to answer instead ol the finely-divided platinum, 
still the principle by which the advantage is gained will be the 
same. However, the battery which I now propose is to be 
made of either copper plated with silver, silver, palladium, or 
platinum. The silver can be rolled to any thinness, and 
therefore is not expensive. Each piece of metal is to be 
