THE DESCENDING SMOKE.

Set a lighted candle on a plate, and cover it with a tall receiver. The candle will continue to burn while the air remains, but when exhausted, will go out, and the smoke from the wick, instead of rising, will descend in dense clouds towards the bottom of the glass, because the air which would have supported it has been withdrawn.

HALF EAGLE AND FEATHER.

Place a nicely-adjusted pair of forceps at the top of the receiver, communicating with the top at the outside through a hole, so that they may be opened by the fingers. Then place on each of the little plates a half-eagle and a feather. Exhaust the air from the receiver, and having done so, detach the objects, so that they may fall. In the open air the half-eagle will fall long before the feather, but in vacuo, as in the receiver now exhausted of its air, they will fall both together, and reach the bottom of the glass at same instant.

THE SOUNDLESS BELL.

Set a bell on the pump-plate, having a contrivance so as to ring it at pleasure, and cover it with a receiver, then make the clapper sound against the bell, and it will be heard to sound very well; now exhaust the receiver of air, and then, when the clapper strikes against the sides of the bell, the sound can be scarcely heard.

SOUNDLESS BELL. FLOATING FISH.

THE FLOATING FISH.