Prof. Loomis on Electricity of Zinc buried in the earth. 9 
amount of zine surface buried in the earth, and the ordinates 
represent the intensity of the electric current, assuming the inten- 
sity to be proportioned to the tangent of the angle of deviation 
of the galvanometer. 
From these experiments it appears that a small wire of zinc 
inserted half an inch in the ground affords a current half as strong 
as a plate an inch square; and a plate one inch square affordsa 
current more than half as strong as a plate one foot square; so 
that even less advantage is gained by 1 a the surface of the 
zinc plate than the surface of the copper 
Exp. 58. I took a strip of sheet zinc feels of an inch 
wide and twenty inches long, and having soldered to it a copper 
wire sixty feet long, inserted it vertically in the ground near the 
Philosophical Hall. Upon dropping the end of the copper wire, 
Exp. 7, seven hundred and sixty feet in length, into the well 
without any plate attached, the needle settled at 382°. This 
current worked the telegraph with promptness ‘or, efficienc 
The following experiments, No. 59 to 65, were tried with 
the electricity of the common machine. 
x . A Leyden jar having a Pian of one quart was 
charged with the electricity of a common machine, and the 
charge passed through the long nanan used in Exp. 7. The jar 
rested upon a table with a wire attached to the zine plate under- 
neath it. Upon bringing the wire attached to the copper 
pi ‘. 
near to the knob of the jar the charge pageedt apparently without 
difficulty. 
Exp. 60. Tapplied my left hand to the outside of the jar 
which rested upon the zinc wire as before. Ou bringing the 
other wire which I held in my right hand near the knob, the jar 
was aeaeer and I receive da severe shock. 
Exp. pe 
circuit No. 2. I again received a shock, but much feebler than 
a cirenit through which the jar was discharg- 
> experinents, offered so much resistance to the 
passage of the fiuid, that at least a portion of the charge preferred 
rout e e through my body. In order to determine 
earth, the follc wing experiments ware tried. 
Exp I took a copper wire ,'; of an inch in diameter and 
one hundred and twenty feet ional and arranged it round the 
Philosophical Hall so that I could discharge ‘a jar through the 
enti length or any portion of it at pleasure. When I discharg- 
ed the jar through thirty feet of wire, I perceived not the slight- 
shock, although I held one end of the wire in my right hand, 
_» and with my left hand clasped the outside of the j Jat. 
Ropgen Gxasae, Vol. IX, No. 25.—Jan., 1850. 
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