by the clock to empty itself of water. By means of a simple water gate one of the 21 equal streams is entirely turned into the garden to be irrigated.

The khammes plunges his gourd into the stream, fills it to the brim, and hangs it up and ties a knot into a long fiber of palm leaf to keep count of the number of periods. As soon as the gourd is empty the khammes refills it and ties a second knot.

He keeps this up until his number of periods have come to an end. The water gate is closed, the gourd wiped, and the small hole at the base carefully plugged to prevent sand and dirt from clogging the aperture.

Four hundred and seventy-nine_khammes are employed in the oasis of Tozeur. The occupation descends as a rule from father to son and the men are greatly respected. At Tozeur the volume of water used during the period it takes a gourd to empty itself (five minutes) is equal to ten cubic meters* (2,641 gallons) and such a water right is bought and sold in perpetuity for 120 to 180 francs.

The volume of water varies at each oasis. The combined springs at Tozeur have an output of 740 liters a second, or 44 cubic meters a minute and 63,936 cubic meters every 24 hours, which is equal to 16,879,104 gallons. The oasis of Nefta has a total output of over 800 liters a second.

Of course, these two oases are especially favored by nature; curiously enough, the more abundant the water the less the natives use it for performing their ablutions. Never have we seen such filthy natives as at Tozeur and Nefta. They use sand instead of water.

Between Nefta, Tunisia, and Biskra, in Algeria, in a region called Souf, there are to be found curious oases.

The most important is called El-Oued; it is a large and wealthy native town, and there is a French military outpost. The natives centuries ago dug enormous holes

*I liter contains 2.113 American pints, or 1.76 English pints.

I cubic meter contains 264.18 American gallons of 231 cubic inches.

I meter is equal to 39.37 inches.

I kilogram is equal to 2 1/5 pounds avoirdupois.

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in the sand and planted palm groves in the holes, which were so deep that the roots of the palms have sufficient moisture throughout the year. A continual war is waged by the inhabitants of ElOued against nature, for each sandstorm, and these are many, tends to fill in the holes, and all the sand that is blown in has to be taken out again in small baskets (see pages 105 and 114).*

Most of us think of an oasis as an ideal cluster of tall palm trees with a beautiful pool, in which is reflected the azure sky and the waving palm leaves. Time and again while riding over the borders of the Sahara we have looked up and seen such an oasis with a wonderfully limpid lake, but it was a magic oasis that vanished on our approach, and the blue lake turned into scorching yellow sand-an optical illusion, a mirage!

Oases vary in size and are measured by the number of date palms in them; a small one contains several hundred palm trees and a large one 300,000 or 400,000.

A LEGEND OF THE DATE PALM

The Arabs call the palm tree "My Aunt," and say that it resembles a human being more than any other variety of

tree.

"Cut off its head and the palm will die. Its head likes sunshine and its feet (roots) like moisture."

An old Arab legend runs something like this: "When Allah created Adam, a few grains of dust fell between his fingers; these grains made the palm

trees.

Another legend runs as follows: "The Emperor of Byzantium wrote one day to the Caliph Amor Ben El Khattab: 'It has been told me that in your country there grows a tree that bears pods, the shape of which reminds one of donkey's ears; when these open they expose to view a substance of immaculate whiteness, as white as milk, which afterward becomes the green color of an

*See also "The Country of the Ant Men," by Thos. H. Kearney, in the April, 1911, number of the NATIONAL GEOGRAPHIC MAGAZINE.

Translated from the Arabic Commentaries of Iman Ibn Amor Ibn Chabbath by Monsieur Lucien Fleury, who has kindly permitted the writer to use his unpublished work.