318 Mr. Smee o« the Galvmiic 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 

 maybe 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 



