21. Sacrificial Vessel which flows only when Moneyis introduced.
If into certain sacrificial vessels a coin of five drachms be thrown, water shall flow out and surround them. Let ABCD (fig. 21) be a sacrificial vessel or treasure chest, having an opening in its mouth, A; and in the chest let there be a vessel, F G H K, containing water, and a small box, L, from which a pipe, L M, conducts out of the chest. Near the vessel place a vertical rod, N X, about which turns a lever, 0 P, widening at 0 into the plate R parallel to the bottom of the vessel, while at the extremity P is suspended a lid, S, which fits into the box L, so that no water can flow through the tube L M : this lid, however, must be heavier than the plate H, but lighter than the plate and coin combined. When the coin is thrown through the mouth A, it will fall upon the plate H and, preponderating, it will turn the beam 0 P, and raise the lid of the box so that the water will flow: but if the coin falls off; the lid will descend and close the box so that the discharge ceases.