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on which hardly anything else is found but  salsolaceous 
plants and tamarisk and a species of Orobanche living on their 
roots. The immense masses of moving sand which have 
accumulated in the low-lying desert mainly through the action 
of the wind which sweeps the sand away from the higher-lying 
ground, is a great drawback, which, however, is not without 
its compensation. In this region, though it looks excessively 
desolate away from the oases, there is under the sand in the 
depressions plenty of water which can be tapped. By means 
of artesian wells, the French have increased the number of 
date-palms enormously, and thus have added greatly to the 
comfort and wealth of the natives, as well as the French 
settlers. When I visited this part of the Sahara in 1909, 
we travelled by caravan from Biskra to Tougourt and thence 
east to El Oued, traversing east of Tougourt the country of 
large dunes of moving sand, which looked most formidable. 
For an Entomologist such a sandy waste far away from the 
vegetation of an oasis at first sight appears to be a hopeless 
locality; nevertheless on favourable nights the lamp attracts 
a fair number of insects. When collecting in the Sahara one 
must discard the idea of large numbers of species, to which 
one has got accustomed in the mountains of Europe, the Tell 
and even on the High Plateaux; on the other hand, the species 
one does get on the sands are generally treasures, and that 
makes up for this paucity in specimens. El Oued is a good 
example of a type of oasis in deep sand. The surface sand 
and the layer of gypsum below it have been removed in places, 
and the palms been planted in the moist sand lying on the 
bottom of the river bed. The oases thus created are hollows 
20 to 30 ft. below the surrounding country, and from some 
distance the tops only of the palms are visible. Instead of 
the water being raised to the surface, the oasis is sunk to the 
level of the water. It took us about twenty-eight days 
to travel from Biskra and back; but our progress was much 
slower than that of a travelling caravan, as we collected 
wherever we camped. Now there is a railway from Biskra to 
Tougourt, which traverses the distance of 110 miles in about 
nine hours, instead of five days, if the engine does not break 
down; there is no speed limit in the Sahara. And as the result 
of the railway, Tougourt rapidly loses the charm of a native 
