4 Prof. Loomis on Electricity of Zinc buried in the earth. 
This then constitutes a most convenient and economical bat- 
tery. The first expense of the plates, without the connecting 
wire is about two shillings. The battery requires no attention — 
from day to day—involves no expenditure for acids—is perma- 
nent in its action—and appears to possess every desirable quality 
for a ag for short distances. 
one of the preceding experiments was the wire which 
formad the circuit wound into a coil, but was stretched out into 
a long line. 
Exp. 13. On the Ist of June, 1849, the galvanometer on the 
long circuit, Exp. 7, settled at 619: on the short circuit, Exp. No.2, — 
it settled at 66 6°. This is the same as was observed May 15th, , 
the day on which the zine plate was first buried; although in — 
one instance after a rainy day, an observation of 70° had been — 
recorded. The current during these seventeen days had been re- 
markably uniform 
I now buried a second zinc plate twenty inches square by the 
side of the former one, at the depth of two feet beneath the sur- 
' face of the earth, and connected the two plates by a short wire. 
\ 
se he galva anometer on the long circuit settled at 664°; on the 
short cireuit it settled at 72°. Thus it appeared that by the 
_ addition of the second zine plate which was considerably larger 
than the first, the strength of the electric current had been in- 
creased about one-third. 
The following experiments were performed to determine the 
influence of the size of Bemeppper plate upon the intensity of the 
current. 
Exps. 14 to 29. I detached ‘copper plates Nos. 2 and 3 from 
the long wire, and substituted for a a single copper plate forty- 
eight inches ays fourteen immersed it ithe well. The galvanome- 
ter stood a 
I now divided the copper plate in 
twenty-four inches by fourteen i immer 
vanometer stood at 71 
I thus proceeded to ‘vide the copper slate" 
it to three inches by a half inch; after which 
tirely rem ; then withdréw the zinc 
th ae leaving a plate 
ithe well. The gal- 
1 I had reduced | 
In the following table, column second shows the 
of the copper plate employed; column third shows 
surface of copper i mmersed, ineluding both sides of the p 
and also the immersed wire; column fourth shows the observet 
aoe of the galvanometer needle; and column fifth ~~ 
tangent of the angle of deviation. 
