If into a vessel, provided at the bottom with an open spout, liquid is poured, the spout shall sometimes run from the first, sometimes when the vessel is half filled, and sometimes not until the whole is filled: in fine, when any proposed quantity of liquid has been poured in, the spout shall run until all is exhausted.
Let A B (fig. 34), be the vessel, the
neck of which is closed: insert the tube C D, air-tight, through the
partition, and let it reach to the bottom of the vessel leaving only a
passage for the water. Let E F G be a bent siphon the inner leg of
which extends nearly to the bottom of the vessel while the other
projects without, being fashioned in the shape of a water-spout: the
curve of the siphon must be close to the neck of the vessel. In A B
make an air-hole, H, near the partition and leading into the body of the
vessel. If we intend the spout to run immediately on the entrance of
the liquid, we must place the finger on the vent H, and the spout will
run, for as the air in the vessel has no wav of retreat, the liquid will
rush out through the bent siphon. If we do not close H, the liquid will
pass into the body of the vessel, and the spout cannot run until we
again close the vent: and then, if we set the vent free, the siphon will
exhaust all the liquid.