Self-sustaining Voltaic Battery. 49 
charcoal, stones, &e:, and is alloyed with various metals, but 
chiefly with iron. As the action of the solvent reduces the sur- 
cle of foreign matter on the zine surface acts as a conducting 
Plate to it, evolving hydrogen from the electrolyte, and most 
rapidly constining both the zine and the solvent. : 
f now the zine plate is mercurialized, the enormous cohesive 
force of the meret causes it to contract over the particles of 
carbon, iron, &c.,,and the surface of the plate is made homoge- 
peous, and consequently as the particles which evolved the hy- 
drogen are now excluded from the electrolyte, their action on it 
ceases. The mercury itself, if more strongly charged with zine 
Stcon Sznizs, Vol. XXI, No, 61.—Jan, 1858. ae eS 
MU. BOT GARDEN 
