In case of need, every oasis becomes a fortress. Each “square of flowery ground” is a redoubt; the assailant’s bullet lodges in the earth wall, or if it pierces through, forms a new loophole in which the Arab plants his gun to aim at his enemy. The villages themselves are encircled with walls, flanked by towers, which remind the spectator of the picturesque fortifications of mediæval times.
The Date-Palm (Phœnix dactylifera) is the tree of the Desert; there only will its fruits ripen; without it, the Desert would be uninhabitable and uninhabited. Arab poesy represents it as a living being, created by God on the sixth day, at the same time as man. To express under what conditions it prospers, the imagination of the Saharan exaggerates the true, to render it the more palpable. “This king of the oasis,” he says, “must plunge his feet in the water and raise his head in the fire of heaven.” Science, to a certain extent, confirms this seeming hyperbole; for it needs 5100° of heat accumulated during eight months for the date to ripen its fruit perfectly. If the sum of heat be less, the fruits set, but they do not grow to their full dimensions, remain bitter to the taste, and fail in the sugar and farina, which form their nutritive properties.
These conditions are realized in the climate of the Sahara. The mean temperature of the year averages from sixty-eight to seventy-six degrees, according to the locality. The heat commences in April, and does not cease until October. The thermometer seldom sinks in the cold season more than two degrees below zero, and the date can endure six degrees below zero.
Rain, as already stated, is rare in the Sahara; it falls in winter, and stimulates into a newly awakened life the vegetation which has been drained of vigour by a summer sun. Sometimes they descend in torrents, but these torrents, like our summer showers, are of briefest duration. At Tongourt and Ouraegla whole years pass by without a drop of rain. Does not the reader understand, then, the gratefulness of the Arabs towards a tree which can derive its nourishment from the burning sand, the scarcely less burning airs of heaven, and the brackish waters beneath the soil which are fatal to all other kinds of vegetation—which retains its verdure fresh in the glare of a pitiless sun—which resists successfully the winds that bow to the ground its flexible stem—which provides him with beams and coverings for his tent, cordage for the harness of his horses and camels, fruit to satisfy his hunger and wine to quench his thirst—which is, moreover, “a thing of beauty,” and gladsome to the eye?
“Those groups of lovely date-trees bending
Languidly their leaf-crowned heads,
Like youthful maids, when sleep descending,
Warns them to their silken beds.”[70]
What the vine is to the Italian, the oak to the Englishman, the cocoa-nut tree to the Polynesian, is the date-palm to the Arab. And more—far more. This single tree has peopled the Desert. A civilization, rudimentary compared with that of the West, sufficiently advanced if you contrast it with that of the Malay or the South Sea Islander, finds in it its standing-point, its centre, its support. And without it the tribes of the Sahara would cease to be.[71]
The wealth of an oasis is computed by the number of its palm trees. All of them, however, are not fruitful; for the date is diœcious. It has its males and its females. The males have flowers furnished with stamens only, and form a closed-up, folded, grape-like ball, previous to the ripening of the pollen in an envelope called the spathe. The females, on the contrary, bear clusters of fruit also wrapped up in a spathe, but incapable of development until fecundated by the pollen or dust of the stamens. To multiply the date-trees, the Arabs do not sow the kernels of the fruits, though they germinate with extreme facility, for it is impossible to tell beforehand of what sex the tree will be; they prefer, therefore, to detach a slip from the trunk of a female tree, and this becomes fruitful at the expiry of eight years.
The male trees blossom, says Mr. Tristram,[72] in the month of March, and about the same time the case containing the female buds begins to open. To impregnate these, a bunch of male flowers is carefully inserted and fastened in the calyx. Towards the beginning of July, when the fruit begins to swell, the bunches are tied to the neighbouring branches.
The dates are ripe in October, at which time any premature rain is fatal to the crop, though the roots require a daily watering. Not less injurious are east winds in March and April. The tree when it begins to bear is about seven feet high. Each year the lowest ring of leaves falls off, so that the age of a palm may be roughly computed from the notches on its stem. Its fruit begins to decline after a century, and the tree is then cut down for building purposes; but it will live for at least a couple of hundred years. Some trees produce as many as twenty bunches, but the average in a favourable season is from eight to ten bunches, each weighing from twelve to twenty pounds. Before the dates ripen, each proprietor is bound to set apart one tree in his garden, whose fruit is consecrated for the service of the mosque and the use of the poor.
From the juice of the date the Arab obtains a sweet fermented liquor, called “laguni,” of which he is inordinately fond. He makes an incision in the top of the tree, taking care to strike home to the centre. A funnel is attached, by which the sap flows into a vessel at the rate of about three quarts every morning for ten to sixteen days. The incision requires to be opened afresh daily.