PHYSICAL FEATURES. xlvit 
ments of the Mediterranean. In the neighbourhood of these lakes, between the two 
deserts, is a tract of land lying almost at the level of their waters and covered with a 
low scrubby vegetation. To the west of Lake Maryut low, rounded, detached ranges of 
hills extend to the south-west, their stony slopes covered, more or less, with a variety 
of plants, and the depressions between them, near the lake, yielding crops to the 
inhabitants of some straggling villages. 
Owing to its proximity to the Mediterranean, the Delta, but more especially the 
region of the lakes, is subject to all the vicissitudes of the climate of that sea, the 
south-eastern extremity of which, however, is not liable to a heavy rainfall. Winter 
is the season of rain, and, on the coast at Alexandria, the mean annual rainfall, from 
1873 to 1881, was 215 - 70 mm., whereas, at Cairo, the mean annual discharge is 
only about 33 mm. The former city is now and again visited in winter by storms 
of rain accompanied by high winds, which in their destructive effects, on the trees 
of the gardens in and around the city, almost remind one of the havoc wrought by 
an eastern cyclone. These storms make themselves felt even as far as Cairo, where 
the rain occasionally falls in such quantities as to flood the streets. They may also 
reach the plateau of the desert between Gizeh and Sakkarah, and crossing the valley 
precipitate themselves, sometimes accompanied by hail, in such torrents on the 
mountains near Heluan that the floods in their rush to the Nile scour out the deep 
wadis of the desert and have been known to carry away even a village and railway- 
culvert in their course. The Mediterranean storms from the north-west also, now 
and again, extend to Suez, even as late as April, when the rain may fall for many 
hours as a cold drizzle driven by a strong wind. 
The air of the Delta contains a considerable amount of moisture, especially abundant 
during the prevalence of sea-breezes, and at night it precipitates itself as a heavy dew, 
exercising a wonderfully refreshing influence on vegetation. 
The mean annual temperature of the Delta, at the sea, is about 20° Cent., and that 
of Cairo is about two degrees hotter. The mean winter temperature of the former 
area is 14° - 44 Cent., and the mean summer temperature 30°. The winter and spring 
mean temperatures of Cairo are somewhat lower than the corresponding means of the 
coast-line, whereas its summer heat is greater. 
The reptiles of the Delta are chiefly found on the semi-desert areas that enclose it, 
on those skirting the lakes, and along the coast-line with its sand-dunes ; but many 
species have also a wide range over the Delta proper, as they appear generally wherever 
there is elevated ground. Only one species of the caudate batrachians is known to be 
present in the Delta ; but although the species of the ecaudate section do not exceed 
five in number, some of them are represented during the period of high Nile by 
multitudes of individuals. 
