* 
10 Prof. Loomis on Electricity of Zinc buried in the earth. 
Exp. 63. When forty feet of wire were introduced, the shock 
would not probably have been noticed, if it had not been a par- 
ticular object of attention. Wit sixty fet of wire the shock 
as so slight that it might have escaped notice under ordinary 
circumstances, but when I clasped the wire very firmly in my 
hand, the shock was quite decided. With one hundred and 
twenty feet of wire ae shock was felt in both my wrists and 
slightly up to my elbow 
xp. 64. In order nie ‘obtain some measure of the amount of 
resistance which this current was capable of overcoming, I took 
two cat-skins prepared for electric experiments with their fur 
upon them. One of them was lined with cotton cloth, cotton 
batting and silk. I doubled each of the skins and laid them to- 
gether so as to make four layers of fur, the whole being nearly 
an inch thick when well cofnpressed. When I discharged the 
jar through the short circuit, as in Exp. 61, my right hand being 
protected by four thicknesses of fur, I perceived no shock. | 
Exp. 65. When the jar was discharged through one hundred 
and twenty feet of wire as in Exp. 63, my hand being protected 
by four thicknesses of fur, I received a sensible shock. With 
six thicknesses of fur I perceived no shock, except when some 
part of my hand or wrist was allowed to come within an inch of 
the unprotected wire, in which case I received a severe shock, 
although I held eight or more thicknesses of fur in my han 
Similar experiments were tried with from one to two hundred 
folds = ny and with similar results. 
ength of wire employed in Exp. 65 was but slightly 
gibt than the wire employed in Exp. 64; and was considera- 
bly less than the entire circuit employ ed in that experiment incelud- 
ing the earth. Hence we must conclude that the twenty-seven 
feet of earth included in the circuit of Exp. 64, offered no appre- 
lectric fluid. It is infer- 
red, therefore, that the resistance detect d in Exps. 60 and 61 
was due mainly if not entirely to the lengtt of Wire in the 
eireul " 
It is remarkable that the electricity of a singlet zine plate should 
traverse this long circuit so freely, while the electricity of a 
eharged jar seeks in preference the circuit through the human 
body, although protected by a considerable thickness of, the poor- 
est conductors known. i 
The following experiments were made to determi inte 
ence of the length of the conducting wire upon the tay | of 
the current. 
Exp. 66. I attached a copper plate fourteen inches ihe twenty- 
four to the end of the wire which was immersed in the well. 
1 then added six hundred and thirty feet more of wire, Pane 
the length of wire in the circuit felted hundred and fifty feet 
esha 
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