[Illustration: Diagram of apparatus as described in text]
The construction of a drinking-horn such that, if a cover of glass be
placed upon it, while a discharge is going on from the vessel, the
liquid shall ascend into the glass cover and be thrown back. A B C
(fig. 52), is a drinking-horn, closed by the covering D E; and from D E
extend two tubes, F G, H K, one of them, H K, leading into the interior
of the vessel, the other, F G, leading outside. A glass cover, M N,
incloses this; and in the top, D E, outside the glass vessel, is an
aperture, X, through which water may be poured. When the horn is filled
through this aperture, the tube H K will be filled at the same time,
and as the water is poured in it will ascend into the glass vessel so
as to be carried outside through the tube F G. Thus we shall have the
arrangement of a bent siphon, of which H K is the smaller leg and F
G the greater, so that it will attract the liquid in the horn as it
ascends into the cover; it will also attract the air contained in the
cover, which is lighter than the liquid, and the water will appear to
be thrown back into the void space left by the air and to descend by
its own weight; for this upward motion is contrary to its nature.