The pneumatics of Hero of Alexandria

The pneumatics of Hero of Alexandria, headed “Inventions of the Ancients,” gives numbered entries such as a siphon which is capable of discharging a greater or less quantity of Liquid with uniformity. The siphon entry says a discharge can be produced that is at once uniform and variable, one in which, for a certain time at pleasure, the stream continues uniform from the beginning. One entry describes a jar in which, if wine is poured in to fill the chamber B C D and then, closing the vent, water is poured upon it, the two cannot mix.

Another entry, headed A Water Jet produced by mechanically compressed Air, says a hollow globe, or other vessel, may be constructed into which any liquid poured will be forced aloft spontaneously and with much violence. A section says that if, before perforating the bottom, the vessel is raised vertically and turned up, its inner surface will be found entirely free from moisture, exactly as it was before immersion, and concludes that the air is matter.