86 Professor Fournet’s Researches on the 
length, from the Atlantic to India, would be about 2100 
leagues; that is to say, about a fourth of the terrestrial cir- 
cumference under the tropic. 
According to the other method of viewing the facts, their 
axis from Arabia, as far as Chinese Mongolia, where there 
is the Schamoon-Gobi, would be parallel to the coast of the 
Indo-Chinese seas, and would run from north-west to south- 
east, like the axis of the great soulevement of Central Asia. 
In this case, we must add to the length already given, the 
five hundred leagues attributed to the Gobi; lat. 47° N. 
would be reached, and the deserts would penetrate consider- 
ably into the temperate zone, which, in that part of Asia, is 
subject to much more violent climates than Europe,—a cir- 
cumstance essential to be remarked in the discussion of the 
facts presented to us by these different places. 
In the whole of Syria and Arabia, the deserts comprised 
between Aleppo, Bassora, Rostak, Mecca, and Damascus, ap- 
pear, at the first glance, to expand from the heights of Ye- 
men, of Hadramaout, and of Mahra, or from the 16th to the 
36th degree N., and the dryness of that surface is well 
known; but we can divide it into two portions, the one 
northern and the other southern, separated by the Nedsjed, 
a varied oasis covered with pastures, watered by springs, and 
inhabited by numerous ‘tribes, to which succeed, on the one 
hand, the country of Bahrein, rich in dates and wine, and on 
the other, the district of Lahsa (/’ Aisa), watered by a river 
which falls into the Persian Gulf, and which is only a tor- 
rent liable to be dried up during the summer. 
The northern portion, known under the name of Barria, or 
of Bar-Abad, and which may be designated by the collective 
name of the Syro-Arabian desert, receives, especially towards 
the northern limit, more or less abundant rains in winter, 
during the months of December and January. These rains 
cause the existence of a particular Flora, and various tribes oc- 
cupy the savannahs, which are surrounded by naked and arid 
tracts. It would be incorrect, therefore, to consider this as 
a desert, or mer-sans-eau, properly so called, although it 
sometimes happens that an entire year passes without rain, 
even in the Nedsjed, where famines are thus produced. It 
