In the porticoes of Egyptian temples revolving wheels of bronze are placed for those who enter to turn round, from an opinion that bronze purifies. There are also vessels of lustral water, from which the worshippers may sprinkle themselves. Let it then be required so to construct a wheel that, on turning it round, water shall flow from it to sprinkle the worshippers as we have described. Behind the entrance-pillar let a vessel of water, A B C D (fig. 31), be concealed, having a hole, E, perforated in its base. Underneath the base let a small tube, F G H K, be fastened, having also a hole bored opposite the orifice in the base, and within this place another tube, L M, soldered to the tube F G H K at L, and opposite the orifice having in like manner a hole, S: between these two pipes let another pipe, N X O R, be closely fitted, with a hole at P opposite to E. Now, if the several holes are in one line, when water is poured into the vessel A B C D it will flow out through the pipe L M; but, if the pipe N X O R is made to revolve so as to change the position of the hole P, the discharge will cease. Attach the wheel to the pipe N X O R, and, if it is repeatedly made to revolve, water will flow out. 32. _A Vessel containing different Wines, any one of which may be liberated by placing a certain Weight in a Cup._ If several kinds of wine be poured into a vessel by its mouth, any one of them at choice may be drawn out through the same pipe: so that, if several persons have poured in the several wines, each one may receive his own according to the proportion poured in by him. Let A B C D (fig. 32), be an air-tight vessel, the neck of which is closed by a partition, E F; and let the whole vessel be divided into as many compartments as we intend there shall be different kinds of wine. Suppose, for instance, that G H, K L, are the partitions, making three compartments, M, N, and X, into which the wine will be poured. In the partition E F pierce small holes, one in each compartment, O, P, R; and from these holes let small tubes, P S, O T, R U, communicating with the vessel, extend up into the neck. Perforate the partition E F, near each tube, with fine sieve-like holes, through which the liquid will pass into the compartments. When it is desired to pour in each kind of wine, place the fingers on S, T, and U, and pour in the wine through the neck Q; it will not pass into either of the compartments as the air contained in them has no outlet. But, if we set free one of the vents S, T, or U, the air contained in the corresponding compartment will pass out through the passage as the wine falls into the compartment. Then, placing the finger again on this vent, set another free in like manner, and pour in another kind of wine: and so in order with the rest, as many as there may be both of compartments and kinds of wine. We may procure each wine, in its due quantity, through the same pipe in the following manner.