THE DESERT
When so much of geographical Egypt consists of desert, it would be interesting if I were to tell you something about it before closing this little book. Probably the first question my readers would ask would be, "What use is it?" Why does Nature create such vast wastes of land and rock which can be of little or no use to anybody?
We cannot always follow the intentions of Nature, or see what may ultimately result, but so far as the desert is concerned we know of at least one useful purpose it serves, and that is the making of climate.
Edinburgh and Moscow are in precisely the same latitudes, yet the one is equable in temperature while the other endures the rigours of an arctic winter. The South of Iceland also suffers less from cold than do the great central plains of Europe. And why? Simply because their different climates are the result of special conditions or influences of Nature, and what the Gulf Stream does for the British Isles the deserts of Africa effect not only for Egypt, but for the whole of Southern Europe, whose genial climate is mainly caused by the warm air generated on these sun-baked barren lands.
Now let us see what the desert is like in appearance. It is a very common impression that the desert is simply a flat expanse of sand, colourless and unbroken; in reality it is quite different, being full of variations, which give it much the same diversity of interest as the ocean.
The colour of the sand varies infinitely, according to its situation. Thus the desert which surrounds Assuan, which is composed of decimated granite and Nile silt, is generally grey; in Nubia the sand is formed of powdered sandstone of a curiously golden tint, while the desert of Suez, which abuts on Cairo and the Delta provinces, is generally white in tone, due to the admixture of limestone dust of which it is largely composed. The great Sahara also is no monotonous stretch of sand, but is to a great extent covered by wild herbs of many kinds, which often entirely screen the sand from view, and give it the appearance of a prairie.
Nor is the desert always flat, for its huge undulations suggest ocean billows petrified into stillness, while rocky hills and earthquake-riven valleys give it a fantastic variety which is wildly picturesque.
Though generally barren, the desert supports growths of many kinds; wild hyssop, thorns, the succulent ice-plant, and a great variety of other shrubs. Flowers also abound, and though they are usually small, I have counted as many as twenty varieties in an area of as many feet, and in some of the deep "wadis," as the mountain valleys are called, wild plants grow in such profusion as to give them the appearance of rock gardens.
In aspect the desert varies very much, according to the time of day or changing effect of light.