The Pneumatics

I. On the Bent Siphon.

Let there be a bent siphon, that is, a tube A B C, of which let the leg A B be in a vessel D full of water; and let the surface of the water be at the straight line in which F G lies: and let the leg A B of the bent siphon be filled with water as far as the straight line F G; that is, let the part A H be so filled, but the part H B C be full of air. If, therefore, we draw out the aforesaid air by the mouth through the orifice C, the liquid will follow at the same time, because, as was said before, a place cannot be entirely empty. And if indeed the orifice C of the siphon is in a direct line with F G, the siphon, having been filled with water, will nevertheless not flow, but will remain full, so that the part A B C of it is replenished with water, although it is carried upward contrary to nature; but the water, having an equilibrium like that of a certain balance