| Prof. Loomis on Electricity of Zinc buried in the earth. 11 
so that the entire circuit, including the four hundred and seventy- 
five feet of earth, was one thousand nine hundred and aranty: 
five feet. The galvanometer settled at 694°. 
Exp. 67. I united the zine wire, Eaxp. No. 58, instead of the 
zine plates, to the long copper wire, making the length of circuit 
P the same as in the last experiment; when the galvanometer 
settled at 474°. 
Exp. 68. I detached five hundred and ten feet of wire, leav- 
ing the length of wire in the circuit nine hundred and forty feet. 
hen this was connected with the zinc plates, the galvanometer 
settled at 693°. 
Exp. 69. I detached three hundred and seventy more feet of 
wire, leaving the length of wire in the circuit five hundred and 
seventy feet; when the galvanometer settled at 7 
Thus it appears that when the length of the aa was doubled, 
the intensity of the current was but slightly impaired, which 
favors the conclusion that the current thus generated might be 
employed for telegraphing to considerable distances. Mr. Vail 
succeeded in telegraphing from Washington to Baltimore with 
such a battery. The size of the plates employed in his experi- 
Exp. 70. I substituted the zine wire for the zine plates on the © 
F same circuit as in Exp. 69, when the galvanometer settled 
at “ame 
eS SS = a = 
A 
. 71. Teconnected the zinc plates | with copper plate No 
on the short circuit, Exp. No. 2, when the galvanometer ssi 
at 724°. 
Exp. 72. I substituted the zinc wire for the zinc plates on 
the id circuit, when the ealgepometer settled at 4 
The preceding experiments were all completed by the 25th of 
June, and no further expe ” el were made until Peplemess 
Seana: 
rved to increase after a ce . It does not ap- 
r however that on the whole the intensity I diminished dur- 
ese five mouths, and it is remarkable that the last observa- 
was the highest made during the entire period, but the ground 
is at this time unusually wet in consequence ot a recent rain. 
