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ell 
On Electro-Dynamie Induction. 239 
distance was tolerably strongly magnetized, as was shown by the 
quantity of filings which would adhere to it. The direction of 
the current was still the same as that of the battery. The form 
of the room did not permit the two wires to be separated to a 
greater distance. The whole length of the circuit of the interior 
large wire was about eighty feet ; that of the exterior one hun- 
dred and twenty. The two were not in the same plane, anda 
part of the outer passed through a small adjoining room. 
123. The results exhibited in this experiment are such as could 
scarcely have been anticipated by our previous knowledge of the 
electrical discharge. 'They evince a remarkable’ inductive en- 
ergy, which has not before been distinctly recognized, but which 
must perform an important part in the discharge of electricity 
from the clouds. Some effects which have been observed during 
thunder storms, appear to be due to an action of this kind. 
124. Since a discharge of ordinary electricity produces a sec- 
ondary current in an adjoining wire, it should also produce an 
analogous effect in its own wire ; and to this cause may now 
referred the peculiar action of: a long conductor. It is well 
known that the spark from a very long wire, although quite 
Short, is remarkably pungent. I was so fortunate as to witness a 
very interesting exhibition of this action during some experi- 
ments on atmospheric electricity made by a committee of the 
Franklin Institute, in 1836. Two kites were attached, one 
above the other, and raised with a small iron wire in place of a 
String. On the occasion at which I was present, the wire was 
extended by the kites to the length of about one mile. 
day was perfectly clear, yet the avails from the wire had so 
Much projectile force, (to use a convenient expression of Dr. 
Hare,) that fifteen persons, joining hands and standing on the 
ground, received the shock at once, when the first person of the 
Series touched the wire. A Leyden jar being grasped in the hand 
by the outer coating, and the knob prosented to the wire, a severe 
Shock was received, as if by a perforation of the glass, but which 
Was found to be the result of the sudden and intense induction. 
125. These effects were evidently not due to the accumulated 
intensity at the extremities of the wire, on the principles of ordi- 
nary electrical distribution, since the knuckle required to be 
brought within about a quarter of an inch before the spark could 
2 received, It was not alone the quantity, since the experi- 
