402 Mr. Davy’s Account of Galvanic Combinations, See. 
the conductors of electricity, and the non-conductors, must be 
alternately cemented into the grooves, so as to form water-tight 
cells. 
When the apparatus is used, these cells are filled, in the 
Galvanic order, with different solutions, according to the 
class of the combination ; and connected in pairs with each 
other, by slips of moistened cloth, carried over the non-con- 
ducting plates. 
A combination of fifty copper-plates, arranged in this manner, 
with weak solutions of nitrous acid, or nitrate of ammoniac, and 
sulphuret of potash, gives pretty strong shocks, rapidly evolves 
gas from water, and affects the condensing electrometer. 
It does not lose its power of action for many hours ; and, when 
this power is lost, it may be restored by the addition of small 
quantities of concentrated solutions, of the proper chemical agents 
to the fluids in the different cells. 
From two experiments made on copper and silver, it would 
appear, that the single metallic batteries act equally well, when 
the metals made use of are slightly alloyed, and when they 
are in a state of purity. 
