To effect this, as I had no proper apparatus near me, I thought to
remove the silk string, and to fasten the twine itself to the chair. I
disengaged the wire which connected the electrometer with the string;
untied it from the silk, and fastened it to the chair: but while I was
effecting this, which took up less than half a minute, I received twelve
or fifteen very strong shocks, which I felt all along my arms, in my
breast, and legs, shaking me in such a manner that I had hardly power to
effect my purpose, or to warn the people of the room to keep their
distance. As soon as I took my hands from the string, the electricity
(in consequence of the chair being a bad conductor) began to snap
between the string and the window shutter, which was the nearest
conductor. The cloud was now just over the kite; it was black, well
defined, and nearly of a circular form, its diameter appearing to be
about 40°; the rain was copious but not remarkably heavy.
As the cloud was going off, I went near the string, and finding the
electricity weak, but still negative, I insulated it again, thinking to
keep it up some time longer; but observing that a larger and denser
cloud was approaching, I resolved to pull the kite in; accordingly a
gentleman, who was near me, began pulling it while I was winding up the
string, he told me he had received two or three slight shocks in his
arms, and if he should feel one more, he would let the string go; upon
which, I pulled the kite in as fast as I could myself, without any
further observation, being ten minutes after four o’clock.
N. B. There was no thunder or lightning perceived that day, nor for some
days before, nor afterwards.
The general laws which Mr. Cavallo deduced from a variety of experiments
made by means of electrical kites, are the following:
1st. The air appears to be electrified at all times; its electricity is
always positive and much stronger in frosty than in warm weather; it is
by no means less in the night than in the day time.
2d. The presence of the clouds generally lessens the electricity of the
kite, sometimes it has no effect upon it, and it sometimes, though
rarely, increases it a little. To this the above mentioned instance is a
remarkable exception.
3d. When it rains, the electricity of the kite is generally negative,
and very seldom positive.
4th. The aurora borealis seems not to affect the electricity of the
kite.
5th. The electrical spark taken from the string of the kite, or from an
insulated conductor connected with it, especially when it does not rain,
is seldom longer than the quarter of an inch; but it is exceedingly
pungent. When the index of the electrometer is not higher than 20° the
person who takes the spark will feel it in his legs; it appearing more
like the discharge of an electrical jar, than the spark taken from the
prime conductor of an electrical machine.
Public-domain text, read in full here on John Shaqi.
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