Syphon

Curved tube in which one end is shorter than the other. The syphon is used to empty the liquid from the pot without inclining; for this reason the short end is put in the pot that contains a liquid, air is siphoned out by sucking from the long end; at this point the draining of the liquid begins and terminates when the long end no longer touches the liqueur. The function of the syphon depends on the air pressure on the surface of the liqueur in the pot, because all the entire surface is equally compressed by the air column. If at a certain point of this surface air pressure is taken away the liqueur flows out at this precise point because it comes across less resistant; this is why the syphon refills intermittently when it sucks air through the long end.