The Sahara
A Natural History
Marq de Villiers,
Sheila Hirtle
(Walker & Co.)

The Sahara is not all sand --- in fact, sand only constitutes 15% of the desert: the rest is rock and gravel. Dunes are not fixed, but tend to migrate, and sometimes inundate whole villages. The Egyptians knew what they were doing --- if they had built cubes instead of pyramids, they would now be fully eroded. Probably 2,000,000 people now live in the Sahara, including some 700,000 nomads.

The main trade of the desert has traditionally been salt, gold, and slaves. Over the centuries, say the authors, the Arabs had "an inexhaustible hunger" for slaves.

A slave was worth much less than a good camel, which was a fair approximation of their relative value. A "good black slave" was about half the price of a good piebald, brindled, or white camel, and was considerably less than the tawny reddish-buff racing camels, so prized for their speed and endurance.

Slavery probably still exists, the authors claim, but the word used now is haratin, which means "vassals." A cynic of Timbuktu once said to them, "Yes, they freed the slaves in 1968, but not all of them have been told yet."

The western Sahara is probably the source of the hurricanes that strike in the Caribbean, and may be as well the source of the "red tide" that devastates fish.

When it rains in the desert, "it rains torrentially, in thunderstorms that cause flash floods" which, on occasion, drown entire caravans. Five major aquifers have been found under the Sahara --- some of which are being tapped, especially in Libya. That one, the Northern Aquifer, is expected to last no more than forty years.

The highest temperature recorded in the desert was in Libya (136° F). The greatest lows have been recorded in the Tibesti mountains, (5° F). A test in Bouroukou, Chad, "measured an evaporation rate of more than 304 inches a year, the highest yet recorded."

In the summer on the mountains the relative humidity is so low it can be life threatening --- 2.5 percent, compared to a "norm" of 30 percent.

The most feared storm is known as the harmattan (like Eskimos with snow, the desert dwellers have many different words for the different kinds of storms).

The coming of the harmattan strips the air of what little moisture remains. Humidity has been tracked to fall from 80 percent to 10 percent within hours. When a gale is in full cry, visibility is reduced to a few yards. Sand penetrates everything. There is grit in the food, grit in the water, grit on the sheets in the hotels. If you close the windows against the sand, as you must, the temperature can climb steadily, and reach 120 degrees, 125 degrees, and the air sears the lungs... Sandstorms can be black as night or a lurid yellow or a bleak gray the color of old ash; they may hiss or roar, or rumble like thunder; the air is oven hot and crackles with static and a hand run over a canvas tent pops and sparks like methane breath on a smoldering coal tip; nerve-ends tingle with electricity and firefly sparks jump and snap. Even camels' tails spark and crackle.

De Villers and Hirtle are elegant writers and they manage to make this story of this, the largest desert on earth, continually fascinating --- never tedious. The writing is lively, often dry (not as in desert, but as in wit), and not so packed with facts that we feel like we are back in Geography 101 again. We get, for example, the history of desert travelers over the years, lessons on surviving in places where there is no water whatsoever within days (freeway users change distance into minutes or hours; for the caravaners, distance in measured in days).

We learn that camels store water in their bellies, not in their humps: that protuberance is the repository of protein, and the authors compare it to protein bars that hikers use.

Too, we learn of the four major ethnic groups of the Sahara, including the Tuareg, whose men rather than the women wear veils. One writer found that Tuareg women tell the men that "a child can 'sleep' in the womb for years, or even forever."

This pious faith gives a frivolous wife a welcome and convenient pretext for representing to her husband in a respectable light any increase in the family that may have taken place in his absence.

Obviously, of the desert dwellers they have met, the authors favor the Tuareg the most. They tell of Tuareg weddings, artifacts, carvings, the rhythm of a caravan, and the impeccable ability of the guides to find their way in a place where the rest of us could see no difference between one dune and the next.

On the subject of desert mirages, they include this dialogue with a Tuareg elder in Agadez:

"There is always water," the old man had said, "in mirages..."

"It's just the heat playing tricks, isn't it?"

"There are always tricks in the desert," the old man said.

"But it doesn't mean anything?"

"Oh, but it does. The water is no-water, but a mirage is a seeing, not a no-seeing."

--- Al Hefid