Section 69
No. 69. A Siphon fixed in a vessel from wiich the Discharge shall cease
at will.
THERE are certain siphons which, when placed in vessels, flow
until the vessels are emptied, or the surface of the water has sunk to
the level of the outer orifice of the siphon. Let it be required that
the discharge shall suddenly cease whenever we wish. A B (fig. 69), is
a vessel containing a siphon, C D E, the inner leg of
which is bent upwards as at C F G. Let a vertical rod H K be fixed, on
which another, L M, works as a lever beam: from L M extends another
rod, M N, moving on a pivot, and provided at the extremity N with a vessel
large enough to encircle the bent portion of the siphon F G. On the
rod L M suspend a weight at L, so that the encircling vessel is raised
above the upward bend of the siphon, and the siphon flows. When we wish
the discharge to cease, we have only to remove the weight at L, and the
vessel at N will descend and encircle the bend G C, so that the siphon
will cease to flow. If it is desired that the stream should continue,
we must again suspend the weight.
Section 70.
Index.