“The spout being closed, the vessel is filled through the tube, Η Θ, before putting water into the pedestal, so that the air may escape through the tube, Ξ Ο. Then, through any aperture whatever, water is poured into the pedestal in such a way as to close the orifice, Ο; and, after this, the spout, Δ, is opened. It is clear that the wine will not flow, since the air cannot enter anywhere. But, if we depress the extremity, Ρ, of the lever, a part of the clepsydra will rise from the water, and the orifice, Ο, being freed, the spout will flow until the water lifted up in the clepsydra has, on running out, closed this same orifice again. If, when the clepsydra has become full again, we still further depress the extremity, Ρ, the liquid in the clepsydra will take longer to flow out, and more wine will consequently be discharged from the spout. If the clepsydra rises entirely from out the water, the flow will last still longer yet. Instead of depressing the extremity, Ρ, by hand, we may use a weight, Φ, which is movable on the external part of the lever and capable of lifting the whole of the clepsydra out of the water when it is placed near Ρ. This weight, then, will lift a portion only when it is farther away from such point. We must proceed, therefore, with a certain number of experiments upon the flow through the spout, and make notches on the lever arm, Ρ Ξ, and register the quantities of wine that correspond thereto, so that, when we desire to cause a definite quantity to flow, we shall only have to put the weight on the corresponding notch, and leave it.”
The miracle of changing water into wine is one of those upon which the ancients exercised their imaginations most. Heron and Philo describe fifteen apparatus designed for effecting this, and more generally for causing different liquors to flow at will from the same vessel.
Here is one of the simplest of them ([Fig. 3]): “There are,” says Heron, “certain drinking-horns which, after wine has been put into them, allow of the flow, when water is introduced into them, now of pure wine, and now of pure water.
“They are constructed as follows: Let Α Β Γ Δ be a drinking-horn provided with two diaphragms, Δ Ε and Ζ Η, through which passes a tube, Θ Κ, this being soldered to them and containing an aperture, Λ, slightly above the diaphragm, Ζ Η. Beneath the diaphragm, Δ Ε, there is a vent, Μ, in the side of the vessel.
“Such arrangements having been made, if any one, on stopping the orifice, Γ, pours wine into the horn, the liquor will flow through the aperture, Δ, into the compartment, Δ Ε Ζ Η, since the air contained therein can escape through the vent, M. If, now, we close the vent, the wine in the compartment, Δ Ε Ζ Η, will be held there. Consequently, if, on closing the vent, Μ, we pour water into the part, Α Β Δ Ε, of the vessel, pure water will flow out through the orifice, Γ; and if, afterward, we open the vent, Μ, while there is yet water above the upper diaphragm, a mixture of wine and water will flow out. Then, when all the water has been discharged, pure wine will flow.
“On opening and closing the vent, Μ, oftener, the nature of the flow may be made to vary; or, what is better still, we may begin by filling the compartment, Δ Ε Ζ Η, with water, and then, closing Μ, pour out the wine from above. Then we shall see a successive flow of pure wine and of wine and water mixed, when we open the vent, Μ, and then, again, of pure wine when the vent is closed anew; and this will occur as many times as we desire it.”
FIG. 3.—HERON’S DRINKING-HORN.
The apparatus represented in [Fig. 4] is very curious, and might be put to some useful application, without mentioning that which wine merchants might make of it by changing the order of the liquids and leaving in view only the vessel, Α Β, and the cock.