Although not strictly connected with the subject, it may be observed that the gourd is probably the original vessel for _heating water, cooking, etc._ In these and other applications the neck is sometimes used as a handle and an opening made into the body by removing a portion of it, as shown in the engraving, its exterior being kept moistened by water while on the fire, while others apply a coating of clay to protect it from the effects of the flame. When in process of time vessels for heating water were formed wholly of clay, they were fashioned after the cauldron as shown. [Illustration: FIGS. 47-52.] The above illustrations are representations of ancient vases; it is curious to note their conformation to the figure of the gourd. The first three on the left are from Thebes. _Golden ewers_ of a similar form were used by rich Egyptians for containing water to wash the hands and feet of their guests. Similar shaped vessels of the Greeks, Romans and other people might be easily produced. In Egypt, India, Chaldea and China the _clepsydra or water-clocks_ date back beyond all records. Plutarch mentions them in his life of Alcibiades who flourished in the Fifth Century B. C. when they were employed in the tribunals at Athens to measure the time to which the orators were limited in their addresses to the judges. Julius Cæsar found the Britons in possession of them. [Illustration: FIG. 53.—WATER-CLOCK.] _The clepsydra is a device for measuring time_ by the amount of water discharged from a vessel through a small aperture, the quantity discharged in a given unit of time, as an hour being first determined. In the earlier clepsydras the hours were measured by the sinking of the surface of the water in the vessel containing it. In others the water ran from one vessel to another, there being in the lower a cork or piece of light wood which as the vessel filled, rose and thus indicated the hour. In later clepsydras the hour has been indicated by a dial. Fig. 53 shows a water-clock described by Hero of Alexandria, Egypt, made _to govern the quantities of fluids flowing from a vessel_. The note below gives the exact wording of the description which has come down to us.