The Sahara Water-Clock

1904

A man's wealth in the Sahara is calculated almost entirely by the number of camels or palm-trees which he owns, and by the amount of water to which he is entitled. Water in the desert is so scarce that the ownership of it is most jealously guarded.

In "A Search for the Masked Tawareks," the author says that in buying a palm grove it is always necessary to stipulate for so many sa'as per day or week. A sa'a, literally "an hour," is the amount of water which will flow in an hour through an opening the width of a man's fist in the side of a segia.

The main segias, or channels, as a rule follow the roads of the oasis, forming a sort of ditch at the side. A regular time-table is kept, showing the hours at which the owners of the different plantations are entitled to draw water.

The time is measured by a very curious little water-clock, consisting of a metal cup, made usually of brass or copper, with a small hole pierced in the bottom. At the commencement of each hour this is placed in a basin of water. The water gradually runs through the hole until, at the expiration of the hour, the cup sinks to the bottom of the basin. It is then taken out, emptied, and set again to measure off the next sa'a, and so the process is continued throughout the twenty-four hours.

This instrument is usually kept in the village mosque. In order to prevent all interference with it, a watchman is set over it, who notifies the expiration of each hour from the minaret of the mosque.

At the end of the sa'a the opening in the side of the segia through which the water flows is closed with clay, and the water is cut off, and allowed to flow down the main channel to the next plantation.