32 3Iemoir on the Ade?i Eesenoirs. [xo. 3, new series, 
A glance at the map of Aden will show, that the range of hills 
\vhich forms the boundary of the crater, is nearly circular, on th^ 
outer or Western side, the hills are very precipitous and the rain 
water descending therefrom is carried rapidly to the sea by means 
of a number of long narrow valleys separate from each other. 
On the inner, or Eastern side, the hills ^are quite as abrupt, but 
the descent is broke^ by a large table land occurring about midway 
between the summit and the sea level, which occupies about one- 
fourth of the entire superficies of the Peninsula. 
This plateau is intersected by numerous deep ravines, nearly all 
converging from the Shumshum range into the Tawela valley, 
which thus receives about a (quarter of the drainage of the Penin- 
sula. 
The steepness of the ravines, the hardness of the rocks and the 
scarcity of soil on them, all combine to prevent any great amount 
of absorption, and thus a very moderate fall of rain suffices to send 
a stupendous torrent of water down the valley, which, ere it reach- 
es the sea, not unfrequently attains the proportions of an unforda- 
ble river. 
The damage done by this torrent has frequently been considera- 
ble, during my residence in Aden I have seen kutcha houses, fur- 
niture, animals, and even human beings carried with irresistible 
velocity into the sea, and during a fall of rain which occurred at 
midnight on the 28th December 1842, so great was the rush of 
water that upwards of two hundred animals, were carried away, 
and nine men were missing in the morning, only three of whose 
bodies were ever found. 
Rain to this extent is exceptional in Aden, but few years pass, 
during which many thousand tuns of water are not lost from want 
of means to retain it. 
Our predecessors were more provident as the gigantic reservoirs, 
which occui chiefly in and near the main water-course, the Tawela 
valley, attest. 
Most travellers have erroneously described them as excavated 
out of the solid rock, but I am not aware of any such. Those under 
