188 G. W. Hough on the Galvanic Battery. 
we have not learned that any one has determined separately 
the resistance due to the cell and that due to the liquids. By 
our method it is necessary to use at least two cells of different 
size. In these experiments three were employed— 
No. 1, White clay cell 0°31 inches in thickness, 6 inches in diame- 
ter and 7 inches high. 
No. 2, White clay cell 0°15 inches in thickness, 8 inches in diame- 
ter and 7 inches high. 
No. 3, Split-leather cell 0-06 inches in thickness, 5 inches in diame- 
ter and 7 inches high, fitted to a bottom of inch pine. 
The resistance of the element was first determined for each 
cell separately. Then the cells were placed one inside of the 
other and the total resistance determined as before. After 
which it was found for two at atime. These several determin- 
ations gave us a series of equations, involving the resistance 
of “ae separate cell together with the specific resistance of the 
quids, ; 
The following are the results expressed in an arbitrary unit. 
No,, 1, resistance, 22 
No..2, = 17 
No. 3, = 7 
Specific resistance of the liquids s. c. saturated solution, 6. 2. 
25° B. 13. From which it appears that the specific resistance 
of the liquids is about the same as for a white clay cell of the 
dinary size. 
As q. is increased by lessening the internal resistance, other 
proper form. It is desirable to perforate the sheet with an or- 
rect punch, in order to secure a more free circulation of the 
liquid surrounding it. Ordinary sheet tin makes the cheapest 
For if the 8. c. solution is not kept saturated, chemical action 
takes plaee between the iron and tin which soon dissolves the 
plates. I have, however, used it successfully. If the solution 
is kept saturated, ina month or so the sheet will be cove 
with a fine plate of copper, which may be easily separated, pro- 
vided the original plate has been properly prepared by being 
oiled and black-beaded before being used. The porous cell in 
