Let there be a vessel containing wine and provided with a spout, underneath which a goblet is placed: whatever quantity of wine is taken from the goblet, as much shall flow into it from the spout. Let A B (fig. 67), be the vessel of wine, and C D the spout, to which are attached the valve E F, and the rods G H, K L, K O, L M as before; and beneath the spout place the cup P. To the rod K O fix a small basin R contained in the vessel S T, and let a tube, U Q, connect the vessels S T and P. When these arrangements are complete, if the vessels S T and P are empty, the basin R will fall to the bottom of S T, and open the spout C D. A stream will flow from C D into both the vessels S T and P, so that the basin will rise and shut the spout again, until we remove more liquid from the goblet. This result will happen as often as we remove liquid from P.