CVI
§ 268. A great many experiments can be made by means
of the electric machine and the Leyden jar, which give us an
insight into the nature of electricity. The most important are
the following: 1) approaching our hand to the conductor of an
electric machine, the neutral electricity in our body is decom
posed, the positive is repelled and the negative is attracted,
If the tension between the opposed electricity is sufficient, they
unite with a crack and a spark, which according to the distance
may be rectilinear or curved, or may take a zigzag shape (light
ning), 430. 2) Sparks may be taken from the human body by
the aid of the insulating stool. 431. (As long as we stand
on this stool the hair diverges.) 3) Upon the conductor of an
electric machine two little bells are suspended by small metal
chains and in the middle another one by a silk thread and con
nected with the ground by a chain; between the 3 bells two small
hollow brass balls are suspended by silk threads. When the
machine is worked by continuous attraction and repulsion the
bells strike alternately against the two balls outside and then
against the middle bell. This is called the electrical chimes.
4) Something similar are the dancing puppets, a light figure
of pith standing between two metal discs, one being connected
with the electrical machine, the other one with the ground.
5) If the conductor of the machine is provided with a point, it
may be shown how points allow electricity to escape (a kind of
draught—the electrical aura—being caused to blow over this
point and a luminous brush appearing, if the experiment is made
in darkness). 432. 6). If on this point a whirl, consisting of
from 4 to 6 wires, terminating in points all bent in the same
direction, is put, this whirl will revolve as soon as the machine
is worked. This is something analogous to Barker's mill
(§ 72). 7) An electrical spark may also produce chemical
