Situation of Zones without Rain, and of Deserts. 87 
results from this, that absolute dryness is hardly to be found, 
except towards the southern extremity of the Arabian penin- 
sula, comprised between the 14th and 23d degrees N. 
The latter is commanded, towards the coast of the Gulf of 
Aden and the Sea of Oman, by the mountains of Hadramaout, 
whose heights do not exceed from 5000 to 5700 feet, and 
from which are derived, on the one hand, the branch of Ye- 
men, running along the Red Sea, and on the other, the branch 
which, starting from Mahra, turns abruptly towards the en- 
trance of the Persian Gulf, and follows, on the coast of Bat- 
na, a south-east and north-west direction, between Ras-al- 
Had and Ras-Muskadom (lat. 22° 23’ to 26° 25’ N.). This 
chain has still, according to the measurements of Lieutenant 
Wellsted, a height of 3000 or 3500 feet, and all these eleva- 
tions are such as must necessarily give rise to the formation 
of rains. The mountains of Hadramaout are also well wa- 
tered ; and between the latter and those of Yemen, the plains 
of Beled-el-Djol, which are sometimes fertile and sometimes 
arid, present streams which preserve their water during the 
whole year, in consequence of the rains of the neighbouring 
mountains. The Nedsjeran receives heavy rains, which fall 
without interruption during the months of December, Ja- 
nuary, and February, while the heights of Yemen, some of 
whose summits receive snow every year, are, on the con- 
trary, fertilized by regular rains corresponding to the summer 
monsoon, and which commence about the middle of June and 
end in September; this season is called Mattar-el-Kharif. 
There is also another, which continues from the month of 
February till April, and which receives the name of Mattar- 
el-Seif ; the more distinctly it is characterised, the more abun- 
dant is the harvest. These rains do not, however, present 
that continuity which exists between the tropics, for the sky 
is rarely clouded during twenty-four hours in succession, and 
the remainder of the year passes without the smallest cloud 
being visible for months together. 
At the foot of these rainy heights, there is met with, on 
the narrow band of coast of the Red Sea, the sandy Tehama, 
which contains so little fertile soil; and where the rains are 
so little abundant, that the inhabitants, with the exception 
