杏吧原创

THE Sahara is one of the great blanks on the map of the world. And 19th-century geographers and engineers abhorred such gaps. At the start of the 1870s, North America had been spanned by the railroad and the oceans were criss-crossed with telegraph cables. But as the 鈥渟cramble for Africa鈥� among European powers got under way, the dunes of the world鈥檚 greatest desert remained untouched.

Enter Fran莽ois 脡lie Roudaire. His ambition was to tame the vast inhospitable salt pans, known as chotts, that spread out in a giant depression to the south, stretching deep into the desert. The chotts were among the hottest spots in all Africa. But when it rained in the mountains, they could fill with water in minutes. Caravans, it was said, disappeared without trace in the flash floods. The salt laid down by the flood waters was so white it could blind a man.

The chotts, moreover, had a mythical resonance, especially for empire-builders. Once, it was said, they had formed a vast sea. The Greek historian Herodotus had written about it in the 5th century BC. There were rumours that the remains of ships had been found buried in the chotts.

The 18th-century English explorer Thomas Shaw believed the chotts were the vestiges of the Sea of Triton in which Jason and the Argonauts were becalmed while searching for the Golden Fleece. For others, the sea had provided the water that turned North Africa into the granary of the Roman Empire. And France, above all, saw itself as the true heir to that empire.

Gazing down on this blinding landscape, notorious for its mirages, Roudaire imagined bringing the sea back into the chotts and using it to regenerate the landscape, perhaps even the climate鈥攖o turn this wasteland into a desert utopia fit for French soldiers, sailors, traders and bureaucrats, and their wives and families.

How would he do it? Simple. The three chotts鈥擬elhrir, el-Jerid and el-Gharsa鈥攚ere mostly below sea level. They were separated only by narrow strips of land, and el-Jerid stopped only just short of the Gulf of Gab猫s in the Mediterranean. So he would harness local labour, just as de Lesseps had in Suez, to dig canals to link them to the open sea.

There were critics. Some thought the sea water washing into the desert would swiftly evaporate under the sun, creating just another layer of salt. Others warned that valuable oases, with their date harvests, would be flooded and there would be plagues of snakes and malarial mosquitoes. But Roudaire insisted that such a large body of water would cool and humidify the air, dousing dust storms and forcing sand dunes to retreat. Clouds would form and generate rain over the nearby Aur猫s Mountains, feeding new rivers to irrigate soils and grow cotton to clothe Frenchmen.

France was eager for such an adventure after its ignominious defeat at the hands of the Prussian army in 1870. The celebrated man of letters Victor Hugo told his countrymen: 鈥淟et us astonish the Universe by great achievements which do not involve warfare. Algeria requires a sea; let us create it there. A sea brings with it ships, ships bring towns, and towns create civilisation.鈥�

Buoyed on this tide, Roudaire and a surveying team headed into the Algerian desert just before Christmas 1874. Walking 20 kilometres a day in the searing heat, suffering fever and hallucinations, they completed the Algerian half of the survey by April. Less than two years later they were back for the Tunisian survey. This time the chotts were wetter and full of snakes. Roudaire鈥檚 Tunisian interpreter went blind after weeks working in the white glare of the salt.

But Roudaire鈥檚 studies concluded that most of the chotts were, as he had hoped, below sea level. The new Sea of Triton could cover 8000 square kilometres, 15 times the size of Lake Geneva. Back home that autumn, Roudaire was the toast of Parisian society.

But French officialdom seemed to have lost its enthusiasm for taming the desert. The commercial failure of the Suez Canal following a boycott by British shipping didn鈥檛 help. Nor did the 1881 slaughter by Tuareg warriors of a French expedition seeking a route for a trans-Saharan railway from Algeria to Sudan.

Roudaire鈥檚 request for funding for the hundreds of drilling cores needed to study the geology of the route for his canal to the Gulf of Gab猫s was denied. In despair, he went home and took to drink. He died from liver failure in 1885.

The days of giant engineering schemes seemed numbered. Jules Verne, whose support Roudaire had courted in the 1870s, made the creation of an inland sea the basis for his last novel, L鈥橧nvasion de la Mer, published in 1905. But in Verne鈥檚 hands, it was a piece of engineering hubris that failed when an earthquake visited havoc on the enterprise.

Nonetheless the idea resurfaced in the 1950s. As Soviet engineers in Egypt helped build the Aswan High Dam鈥攆looding an area half that proposed in Roudaire鈥檚 project鈥擜merican and Tunisian engineers proposed using dozens of nuclear explosions to blast a canal from the chotts to the sea. They figured that evaporation in the desert would maintain a continuous flow of water from the Mediterranean, and that the inflowing water could be used to generate hydroelectricity. In November 2001, during a Global Super Projects Conference held over the Internet, Californian geographer Richard Cathcart again proposed recreating Lake Triton. And Turkmenistan is playing renewed homage to the idea, though the lake it鈥檚 planning is only a quarter the size of Roudaire鈥檚 sea.

But for now the chotts live on, regarded as wildlife havens for wintering birds, and far too valuable to be flooded. Perhaps grand plans for the chotts always were strictly for the birds.