There is another way in which, on lighting a fire, the doors will open. As before, let a small temple stand upon a base, A B C D (fig. 38), on which is an altar, E. Let a tube, F G H, pass through the altar and be attached to a leathern bag, K, perfectly air-tight: beneath this let a small weight, L, hang, from which a chain is attached across a pulley to the chains round the hinges, so that, when the bag is folded together, the weight L preponderates and shuts the doors, and when fire is placed on the altar they are opened. For, as before, the air in the altar growing hot, and expanding, will pass through the tube F G H into the bag, and raise it up with the weight L; and then the doors will be opened. The doors will either open of themselves, as the doors of baths shut spontaneously, or they may have a counterbalancing weight to open them. When the sacrifice is extinguished, and the air which has entered the bag passes out, the weight, descending with the bag, will tighten the chains and close the doors. 39. _Wine flowing from a Vessel may be arrested on the Introduction of Water, but, when the Supply of Water ceases, the Wine flows again._ [Illustration: Diagram of apparatus as described in text] If there be a vessel containing wine, and provided with three spouts, wine shall flow through the middle of the three; and, when water is poured in, the stream of wine shall cease, and water shall flow through the other two; again, when the stream of water ceases, wine shall flow through the middle spout: and this shall take place as often as we pour in water. Let A B (fig. 39), be a vessel, the neck of which is closed by the partition C D, and having a spout, E, at the bottom. Let two tubes, F G H, K L M, terminating in spouts, pass through the partition and project above it; and round the projecting parts place other tubes, N, X, covered with lids at the top and extending to the partition except a passage for the water. Another tube, P, reaching nearly up to the partition, communicates with F G H. Having first closed the spout E, fill the vessel A B with wine through an orifice, Q, which must be carefully closed afterwards. When E is set free it will be found that wine flows through it, for air enters from without into the void created, through the orifice H and the tube P. Now, if we pour water upon the partition C D, it will be carried out through the tubes F G H, K L M; but, as the air has no means of entering the vessel A B, the wine will cease to flow until all the water has escaped, when the air finds an entrance again and the wine flows. Instead of the tube P, another tube, R S, may be used, piercing through the partition, about which another, T U, must lie, like the tubes N and X, but higher than those, so that R S may rise above the lip of the vessel. The same result will follow. 40. _On an Apple being lifted, Hercules shoots a Dragon which then hisses._ [Illustration: Diagram of apparatus as described in text]