d the top end of D. To the outer end of
W tie a silk thread, S T, on the lower end of which may be tied a piece
of pith or material to serve as an electroscope.

[Illustration: Fig. 108.]

APPARATUS 137.

_241. Carbon Electroscope._ Carbon will be found to make a most
excellent electroscope, as it is light and a good conductor of
electricity. Light an ordinary match and let it burn until it is charred
through and through. The black substance remaining is carbon. Tie a
small piece of the carbon, about 1/4 in. long, to one end of a silk
thread, and support the thread as in Fig. 107 or 108.

APPARATUS 138.

_242. Pivoted Electroscope._ Fig. 109 and 110. Fold a piece of stiff
paper double, then cut it into the shape shown. It should be about 3 in.
long and 1 in. wide when opened out. A hole, B, about 1/2 in. in
diameter should be cut in it while folded. A piece of paper, C, should
be pasted to A, so that its top, where it is creased, will be about 1/8
in. above the top of A. The support consists of a pin, E, stuck through
a cork, D. Balance the paper on the pin, which passes up through the
hole, B. An electrified body brought near this apparatus will make it
whirl around very decidedly.

[Illustration: Fig. 109.]

[Illustration: Fig. 110.]

APPARATUS 139.

_243. Fancy Electroscope._ Fig. 111. Fold a piece of stiff paper double,
then cut out some fancy-shaped figure, as suggested, and draw the face,
clothes, etc., to suit. This being folded through the center for
cutting, it can be balanced upon a pin-point as explained in App. 138.

[Illustration: Fig. 111.]

[Illustration: Fig. 112.]

APPARATUS 140.

_244. Box-Cover Electroscope._ Fig. 112. A pasteboard box-cover,
balanced upon a pin, makes a fairly good electroscope, although it is
not nearly so sensitive as App. 138. The pin may be stuck in the upper
end of the dowel, D, shown in Fig. 108.

APPARATUS 141.

_245. Leaf Electroscope._ Fig. 113. This is a very sensitive instrument,
and can be used to tell the kind of static electricity on a body, as
well as the mere presence of it. (See experiments in text-book.) The
lamp chimney acts as a support for the leaves, L, and it protects them
from currents of air. A tin box-cover, C, has a small hole punched
through its center. Through this is pushed one end of a wire, W. This
may be a hairpin, straightened. The upper end is bent over at right
angles, after passing it through the hole. The lower end