114 DESCRIPTIONS OF EGYPT. 
quality, has a strong affinity for water, and suffers 
contraction in the fire. By desiccation in the air, 
its colour is gradually changed from black to a yel- 
lowish brown. When subjected to chemical analy- 
sis, it is found to consist chiefly of alumine or pure 
clay, with a small quantity of silex ; but the pro- 
portions of these ingredients vary according to the 
place where the slime is collected. * In the im- 
mediate vicinity of the Nile, it contains a consider- 
able quantity of siliceous sand, which being most 
ponderous, is soonest deposited. This mud is so 
tenacious, that a considerable intermixture of sand 
increases its fertility ; and hence the soil derives 
some advantage from the rapid winds of the south, 
which convey the sand in immense clouds from the 
desert to mingle with the slime of the Nile. 
As the waters of the river recede, the cultiva- 
tion of the ground commences. If it has imbibed 
the requisite moisture, the process of agriculture is 
neither difficult nor tedious. The seed is scatter- 
ed over the soft mould, and vegetation proceeds 
with extreme rapidity. To the activity of vegeta- 
tion, the air, which is strongly impregnated with 
saline particles, contributes in an eminent degree. 
* According to Regnault's Analysis, the slime of the Nile, 
in 100 parts, contains 11 of water, 9 of carbon, 6 of oxyd of 
iron, 4 ef silex, 4 of carbonate of magnesia, 18 of carbonate 
©f lime, and 48 of alumine. — Memoirs on Egypt, p. 391 . 
