cise. Our
spheres are fixed on iron axes which pass through them. At one end
of the axes there is a small handle with which you turn the sphere
like a common grindstone. This we find very commodious, as the
machine takes up but little room, is portable, and may be enclosed
in a tight box when not in use. It is true the sphere does not turn
so swift as when the great wheel is used; but swiftness we think of
little importance, since a few turns will charge the vial, etc.,
sufficiently.

I am, etc.,
"B. FRANKLIN."

(Read before the Royal Society, December 21, 1752.)

"PHILADELPHIA, 19 October, 1752.
"_To Peter Collinson_:

SIR--As frequent mention is made in publick 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, though made
in a different and more easy manner, which is 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 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 fixed 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