t 



1902.] on the Nile Dama and Reservoir. 193 



designing and manufacture of the sluices and lock-gates ; 140 of the 

 sluices are 28 ft. high by 6 ft. 6 in. wide, and 40 of them half that 

 height; 130 of the sluices are on the " Stoney " principle, with 

 rollers, and the remainder move on sliding surfaces. The larger of 

 the Stoney sluices weigh 14 tons, and are capable of being moved by 

 hand under a head of water producing a pressure of 450 tons against 

 the sluice. 



There are five lock-gates, 32 ft. wide, and varying in height up 

 to 60 ft. They are of an entirely different type to ordinary folding 

 lock-gates, being hung from the top on rollers, and moving like a 

 sliding coach-house door. This arrangement was adopted for safety, 

 as lOUO million tons of water are stored up above the lock-gates, 

 and each of the two upper gates is made strong enough to hold up 

 the water, assuming the four other gates were destroyed (Fig. 6). 



When the river is rising, the sluices will all be open, and the red 

 water will pass freely through, without depositing the fertilising silt. 

 After the flood, when the water has become clear, and the discharge 

 of the Nile has fallen to about 2000 tons per second, the gates with- 

 out rollers will be closed, and then some of those with rollers'; so 

 that between December and March the Reservoir will be gradually 

 filled. The re-opening of the sluices will take place between May 

 and July, according to the state of the Nile and the requirements of 

 the crops. 



Between December and May, when the Reservoir is full, the Island 

 of PhilaB will in places be slightly flooded. As the temples are 

 founded partly on loose silt and sand, the saturation of the hitherto 

 dry soil would cause settlement, and no doubt injury to the ruins. 

 To obviate this risk, all the important parts, including the well- 

 known Kiosk, or " Pharaoh's bed," have been either carried on steel 

 girders or underpinned down to rock, or, failing that, to the present 

 saturation level. It need hardly be said that, having regard to the 

 shattered condition of the columns and entablatures, the friability of 

 the stone, and the running sand foundation, the process of under- 

 pinning was an exceptionally diflacult and anxious task. There were 

 few men to whom I would have entrusted the task, but amongst those 

 was Mat Talbot — one of the well-known Talbots who have done such 

 splendid service as non-commissioned officers in the army of work- 

 men employed by contractors during the past forty years ; and well 

 has he justified his reputation at home — where his last job was the 

 most difficult part of the Central London Railway — and the com- 

 mendation of Dr. Ball, who had charge of the works at PhilaD. 



It would be invidious to single out for special acknowledgment 

 the services of members of a staff, where all have enthusiastically 

 done their best for the accomplishment of the great work projected 

 and patiently persisted in against all opposition, by Lord Cromer 

 and his trusty lieutenant. Sir William Garstin, Under Secretary of 

 State for Public Works. The successive Director-Generals of the 

 Reservoirs were Mr. Willcocks, Mr. Wilson, and Mr. Webb ; the 



Vol. XVIL (No. 96.) o 



