Let there be a vessel containing water, and pipe in it provided with a key or cock, and let a figure float on the surface of the water ; then if water, in any quantity, be drawn off through the pipe, wine shall flow from the figure in any given ratio to the water drawn off. Let A B
(fig. 25) be the vessel of water, provided with a pipe, C, which admits
of being closed; and on the surface of the water let a basin, D, float,
in which is a perpendicular tube, E F, carved in the shape of some
animal. Place near another vessel, G H, containing wine, in which is a
bent siphon, K L M, one leg being within the vessel G H, and the other
without, conducting into the tube E F. Now if we draw the wine through
the lower mouth M, it will flow into the tube E F until the surface of
the wine in the vessel C; H and in the tube E F shall be at the same
level. Let that level be in the line N X 0 P; and at the point P fix an
open pipe, R. Hitherto there is no discharge of wine, but, if any
quantity of water is drawn off through C, the basin D, and, with it, the
tube E F will sink, and the surface of the wine [in the tube] will
become lower than the surface N X; so that, the outer leg of the siphon
being depressed, the wine will again pass on into the tube E F and run
out through the pipe H. This will happen as often as we draw off water
through the pipe C, the wine flowing in a fixed ratio to the water drawn
off. The base of the vessel A B must bear the required proportion to the
base of G H; and thus what was proposed is done.