SYPHONS.
FIG. 1.
FIG. 2.
Syphons are bent tubes for drawing off liquids from cisterns, butts, &c., where there is no tap, and where it would be inconvenient to make any second opening. [Fig. 1] gives the outline of the most usual form of syphon; these are only used for liquids that may be drawn into the mouth without injury, such as spirits from casks. The mode of using the syphon is this—the bottom of the longest leg a is stopped with the palm of the hand, the tap is then turned on and the mouth applied to the small tube c, the air is then drawn out by sucking; the liquid rises and fills both legs of the instrument, the tap is turned off, and the syphon is full. Now as the leg a is longer than the leg b, the fluid in it weighs more than that in b, and sinking down draws the fluid in b up, and so on till all is drawn from the cask. Syphons are generally made of copper, but gutta-percha would answer exceedingly well. [Fig. 2] represents a contrivance for drawing off acids, &c., which would injure the mouth; the ball prevents the acid rising into it, as the mouth is removed directly it begins to fill, which as the instrument is of glass, can easily be seen.
STOP-COCKS OR TAPS.
