Section 53
No. 53. A Vessel in which Water and Air ascend and descend
alternately.
THERE is also another contrivance by which liquid is borne steadily
upwards and remains, so as to seem perpetually ascending.
Let A B (fig. 53), be a perfectly
air-tight pedestal, partition, C D, and a cover, E F, also perfectly
air-tight. In the
cover E F let there be a tube, G H, reaching nearly to the top, and
passing through an orifice in the partition C D, and another tube, K L,
passing through the top of the pedestal but not descending quite so low
as the partition. In the pedestal, and outside the glass cover, let
there be an aperture, M, through which the vessel A D is to be filled,
and near the bottom of the pedestal a spout, N; also one other tube, x
0, passing through the partition and reaching nearly to the bottom of
the pedestal, through which the vessel C B may be filled. If the spout,
N, be closed the air in C B will pass out through the tubes G H, K L,
and the hole M; and when C B is full we must fill A D through the hole M, for the
air contained in it will pass out through the same hole. Now, if we set
the spout N free, the air in the glass cover will pass through the tube
G H into the void space left in C B, and water will ascend from A D
through the tube K L into the void space left in the cover, while into
the void of the vessel A D air
will enter through the aperture M and this will go on until the glass
cover is filled: but the spaces A D, C B, E F, must be of equal capacity
that the air and water may take the place of one another. When C B is
exhausted and the continuity of the air is broken, the water will again
descend out of the glass cover into A D, air passing into the cover
through the spout N and the tube G H. The air in A D will pass out
through the aperture M.
Section 54.
Index.