Galvanic Batteries. 173 
tight under the alternations of wet and dry to which the voltaic in- 
strument is subject. To remedy this evil, Mr. Newman i $ noW enga- 
ged in obtaining porcelain sennghes The other disadvantage is a pre- 
whole Slineeiy a is then reduced. I expect that se using slips of glass 
to separate the coppers at their edges, their contact can be sufficiently 
prevented, and the space between them be left so open that the acid 
ofa charge can be poured and washed out, and be so removed from ev- 
ery part of the trough when the experiments in which it is used are 
completed.* 
* The actual ve sicker 4 of the troughs which I have constructed 
on this plan, I believe to depend, first and principally, on the closer 
su 
coppers is a disadvantage, but I do not find that it is any advantage ; 
for when, with both the forty pairs of three-inch plates and the twenty 
pairs of four-inch plates, I used papers well imbibed with wax,f these 
being so large that when folded at the edges they wrapped over each 
other, so as to make cells as insulating as those of the porcelain 
bes a still no sensible advantage in the chemical action was ob- 
tained 
vantage. The plates need not fastened iD, but only set int eir 
places ; nor need they be in large oie pieces.”’} 
* Dr. Hare has obviated these difficulties by making one trough to go into an- 
other,.the whole being cemented while heated by a flambeau of alcohol, so as not 
only to <a vd the cement liquid, but also to expel the moisture ‘and air from the | 
in refrigerating absorb the cement. ‘The cement was made by melt- 
ing a one part of suet and seven of rosin 
+ A single paper thus prepared could insulate the electricity of atrough of forty 
pairs of plates. 
t Dr. Hare mentioned in his account of his deflagrator made with copper cases, 
‘ that he had found a series in which the side edges were exposed deficient of power. 
He objected to having the cases like those employed by eas open at the sides. 
His cases were closed at the sides, and open above and below 
