CHAPTER XV 
DESERTS 
IN consequence of the world’s rotation, there are certain 
latitudes in which the winds blow in a more or less definite 
direction almost the whole year through. When the 
trend of the coast-line is such that these winds are off- 
shore or parallel to the coast, no rain reaches the land. 
This explains, eg., the nitrate deserts of Chile, the 
Namaqualand and Kalahari deserts in Africa, a small 
patch of very dry country in South Madagascar, and the 
West Australian desert. 
These, however, are but small as compared with those 
of the Northern hemisphere, and especially the great 
Saharan-Central Asian desert which extends from the 
Atlantic to the borders of British India. 
That this world is aged and drying up is by no means 
anew theory. It was a favourite subject for discussion 
with such ingenious scientists as Dr. Maillet and Celsius, 
Prince Krapotkin and others consider that, in our own 
geological period, the world is rapidly drying up, and 
that Asia in particular is kecoming far more desert than 
it used to be.’ It is of course indisputable that, for in- 
stance, the arid and desolate plains of Jungaria were 
once full of inhabitants. Dr, Sven Hedin discovered 
ruins of cities once wealthy and luxurious, with rich 
monasteries and evidence of once carefully irrigated 
fields in Teklamakan, which is now a desert of sand, 
so destitute of water and of forage that that intrepid 
explorer had the greatest difficulty in traversing it. 
Still this does not necessarily prove that there is no 
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