ed its colour, being now all over of a
bluish hue. If cut transversely, the quicksilver will be seen to
glitter in every part of it.

_The Magic Bell._

Fix a small bell to the wire that goes through the top of the
receiver. If you shake the wire, the bell will ring while the air is
in the receiver; but when the air is drawn off, the sound will by
degrees become faint, till at last not the least noise can be heard.
As you let the air in again, the sound returns.

_Feathers heavier than Lead._

At one end of a fine balance, hang a piece of lead, and at the other
as many feathers as will poise it; then place the balance in the
receiver. As the air is exhausted, the feathers will appear to
overweigh the lead, and when all the air is drawn off, the feathers
will preponderate, and the lead ascend.

_The self-moving Wheel._

Take a circle of tin, about ten inches in diameter, or of any other
size that will go into the receiver, and to its circumference fix a
number of tin vanes, each about an inch square. Let this wheel be
placed between two upright pieces on an axis, whose extremities are
quite small, so that the wheel may turn in a vertical position with
the least possible force. Place the wheel and axis in the receiver,
and exhaust the air. Let there be a small pipe with a cock; one end of
the pipe to be outside the top of the receiver, and the other to come
directly over the vanes of the wheel.

When the air is exhausted, turn the cock, and a current will rush
against the vanes of the wheel, and set it in motion, which will
increase, till the receiver is filled with air.

_The Artificial Halo._

Place a candle on one side of the receiver, and let the spectator
place himself at a distance from the other side. Directly the air
begins to be exhausted, the light of the candle will be refracted in
circles of various colours.

_The Mercurial Shower._

Cement a piece of wood into the lower part of the neck of an open
receiver, and pour mercury over it. After a few strokes of the pump,
the pressure of the air on the mercury will force it through the pores
of the wood in the form of a beautiful shower. If you take care that
the receiver is clear and free from spots or dust, and it is dry
weather, it will appear like a fiery shower, when exhibited in a dark
room.

_Magic Fountain._

Take a tall glass tube, hermetically sealed both at top and bottom, by
means of a brass cap screwed on to a stop-cock, a