186 G. W. Hough on the Galvanic Battery. ° 
The relation between the quantity of electricity and the spe- 
from zero to saturation. These were alternately used in the 
porous cell and g. measured by the galvanometer. The time 
tor each experiment was about five minutes. Above the speci- 
fic gravity of 15° B. g. was sensibly the same up to saturation. 
These results were so directly contrary to all our experience 
with the battery in actual use, that at first we were at a loss 
to understand them. e experiments were accordingly con- 
tinued, by putting an element on a closed circuit through the 
galvanometer. The quantity of electricity and the specific 
gravity of the s.z. was then noted from time to time. So soon 
as the s.z. approached near saturation, from 43° to 46° B. de- 
pending on the temperature, it was found that the element 
dually decreased in force until finally g. was less than one 
twentieth of its normal value. As the electro-motive force re- 
in the solution and has been ably discussed by a number of 
scientists. But the polarization in the battery itself does not 
appear to have been investigated. After an element has bee? 
on a closed circuit for a long time, if the circuit be opened for 
a few minutes, on closing it, the galvanometer will at first indi- 
cate the maximum quantity due to the element, but in a few 
seconds the needle will gradually recede and stand as before. 
It appears that when the specific gravity of the s. 2. approaches 
* 
q. reaches its 
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