As frequent mention is made in public papers from Europe of the
success of the Philadelphia experiment for drawing the electric fire
from clouds by means of pointed rods of iron erected on high
buildings, etc., it may be agreeable to the curious to be informed
that the same experiment has succeeded in Philadelphia, tho made in a
different and more easy manner, which is as follows.
[Footnote 22: From a letter to Peter Collinson, dated October 19,
1752, and read before the Royal Society of London in December of the
same year.]
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 corners 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
those 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 fixt a very sharp pointed wire, rising a
foot or more above the wood. To the end of the twine, next the hand,
is to be tied a silk ribbon, and where the silk and twine join, a key
may be fastened. This 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. And when the rain has wetted 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 vial may be charged; and from electric fire
thus obtained, spirits may be kindled, and all the other electric
experiments be performed, which are usually done by the help of a
rubbed glass globe or tube, and thereby the sameness of the electric
matter with that of lightning completely demonstrated.