90 Professor Fournet’s Researches on the 
Nevertheless, five principal deserts have been enumerated 
by authors, of which the one separating Khorassan from the 
Irac-Adjemi, termed the Great Salt Desert, or Kuwir, is, of 
itself, said to be upwards of 300 miles in length, and 170 
miles in breadth; their whole amount, forming ;3; of the su- 
perficies of the country, is comprised between 25° and 36° 
N., from Beloochistan as far as the chain of Elbrouz; the 
latter, which separates the plateau of Iran from the vast hol- 
low of Touran, does not constitute an absolute limit towards 
the north, for moving sands displace rivers between the 
Caspian Sea and the Lake of Aral. But, without occupy- 
ing ourselves with this sort of appendage of the steppes of 
Kirghise or of Ischim, let us confine our investigations to the 
southern portion of the region. 
On the plateau of Iran, there are, first of all, the deserts 
of Khorassan and of Naubendam, above which, it may be said, 
that during the summer no cloud is to be seen; the dews 
are so slight, that paper is not moistened during the night, 
and polished iron is not at all rusted. Vast plains, in the 
midst of which is included the oasis of Yezd (é. e. light), the 
last refuge of the worshippers of fire, present only a dry sur- 
face, covered with a crust of salt, which cracks under the 
feet, and nourishes saline plants. But whatever may be the 
dryness of that region, there is no absence of rain ; for at 
Ispahan (lat. 32° 40’ N.), where the winter commences in No- 
vember and continues until March, there are falls of rain so 
abundant, that the earth is penetrated by it to a depth of 
more than a yard; and there are, moreover, four or five 
pretty considerable falls of snow. The most violent rains 
occur in March and April; they are accompanied by hail ; 
and, at that epoch, strong winds announce the return of the 
droughts. 
In the same latitude, the mountains of Khorassan are 
covered with a thick coating of snow during the winter, while 
rain inundates the subjacent plains ; so that the whole of this 
zone presents the same conditions as the Syro-Arabian desert, 
of which it forms the prolongation towards the east ; but it, 
at the same time, exhibits a greater intensity of cold. 
We have next the desert of Kerman, situated to the SE. of 
