Several philosophers had observed that lightning and electricity
possessed many common properties; and the light which accompanied
the explosion, the crackling noise made by the flame, and other
phenomena, made them suspect that lightning might be electricity in
a highly powerful state. But this connection was merely the subject
of conjecture until, in the year 1750, Dr. Franklin suggested an
experiment to determine the question. While he was waiting for the
building of a spire at Philadelphia, to which he intended to attach
his wire, the experiment was successfully made at Marly-la-Ville, in
France, in the year 1752; when lightning was actually drawn from the
clouds by means of a pointed wire, and it was proved to be really the
electric fluid.
Almost every early electrical discovery of importance was made by
Fellows of the Royal Society, and is to be found recorded in the
_Philosophical Transactions_. In the forty-fifth volume occurs the
first mention of Dr. Franklin’s name, and his theory of positive
and negative electricity. In 1756 he was elected into the Society,
“without any fee or other payment.” His previous communications
to the _Transactions_, particularly the account of his electrical
kite, had excited great interest. (_Weld’s History of the
Royal Society._) It is thus described by him in a letter dated
Philadelphia, October 1, 1752:
“As frequent mention is made in the public papers from Europe
of the success of the Marly-la-Ville experiment for drawing the
electric fire from clouds by means of pointed rods of iron erected
on high buildings, &c., it may be agreeable to the curious to be
informed that the same experiment has succeeded in Philadelphia,
though made in a different and more easy manner, which any one may
try, as follows:
Make a small cross of two light strips of cedar, the arms so
long as to reach to the four corners of a large thin silk
handkerchief when extended. Tie the comers of the handkerchief
to the extremities of the cross; so you have the body of a kite,
which, being properly accommodated with a tail, loop, and string,
will rise in the air like a kite made of paper; but this, being of
silk, is fitter to bear the wet and wind of a thunder-gust without
tearing. To the top of the upright stick of the cross is to be
fixed a very sharp-pointed wire, rising a foot or more above the
wood. To the end of the twine, next the band, is to be tied a silk
ribbon; and where the twine and silk join a key may be fastened.
The kite is to be raised when a thunder-gust appears to be coming
on, and the person who holds the string must stand within a door
or window, or under some cover, so that the silk ribbon may not be
wet; and care must be taken that the twine does not touch the frame
of the door or window. As soon as any of the thunder-clouds come
over the kite, the pointed wire will draw the electric fire from
them; and the kite, with all the twine, will be electrified; and
the loose filaments of the twine will stand out every way, and be
attracted by an approaching finger.
When the rain has wet the kite and twine, so that it can conduct
the electric fire freely, you will find it stream out plentifully
from the key on the approach of your knuckle. At this key the phial
may be charged; and from electric fire thus obtained spirits may
be kindled, and all the other electrical experiments be performed
which are usually done by the help of a rubbed-glass globe or tube;
and thus the sameness of the electric matter with that of lightning
is completely demonstrated.”--_Philosophical Transactions._
Of all this great man’s (Franklin’s) scientific excellencies, the most
remarkable is the smallness, the simplicity, the apparent inadequacy
of the means which he employed in his experimental researches. His
discoveries were all made with hardly any apparatus at all; and if
at any time he had been led to employ instruments of a somewhat less
ordinary description, he never rested satisfied until he had, as it
were, afterwards translated the process by resolving the problem with
such simple machinery that you might say he had done it wholly unaided
by apparatus. The experiments by which the identity of lightning and
electricity was demonstrated were made with a sheet of brown paper, a
bit of twine or silk thread, and an iron key!--_Lord Brougham._[50]