204 EGYPTIAN AGRICULTURE. 



compare with minute canalisation and washing. The 

 State Domains experiments at Bechbiche (see Vol. V N 3 

 of the Journal of the Khedivial Agricultural Society and 

 the School of Agriculture) entirely confirm this opinion 

 that colmatage is slow, costly and unsatisfactory. 



There is a colmatage or warping being tried on the 

 Nile foreshores and byewaters, south of Cairo, by a com- 

 pany, but that is an entirely different thing. It depends 

 on checking the current which then fails to carry the silt, 

 and that is deposited. Part of the sloping bank or 

 foreshore is enclosed with a stone dyke ; water is admitted 

 freely and silt deposited. Or, one of the side branches 

 is dammed at top and bottom, and a large quantity of 

 water admitted by a regulator which when closed stops 

 any current, and the silt at once falls to the bottom. The 

 surface of the land will gradually be raised, more rapidly 

 at first when the depth of water is great, and slower as the 

 level of the land rises. In this kind of warping, the main 

 Nile can be drawn on without limit so long as it maintains 

 the height necessary to cover the land. It is a very 

 different matter to attempt colmatage in the northern 

 delta, with shallow intermittent floodings drawing water 

 from a canal by means of a pipe. 



The washing process on fully drained land continues 

 from September till April, if water is available, and during 

 that period the land is never dried. It might be better 

 to fill up a plot, let the water filter through, and then the 

 land would dry and crack. The next supply of water 

 would penetrate quickly and deeply through the cracks. 

 But on the seaboard there is a rainfall of eight inches, all 



