43 



Efficiency of the sakiyeh ax a vater-roising device. 



Height of lift. 



Number 



of 



animals 



working 



two or 



two and a 



half hour 



periods. 



3 feet 



5 feet 



5.-50 feet . 



6 feet 



7.75 feet . 

 8.75 feet . 

 10 feet . . . 

 12 .50 feet 

 16 feet . . . 

 19 feet . . . 

 5 feet . .. 



Cost of 



running 



machines 



per day of 



ten hours. 



$0.60 

 .60 

 .63 

 .58 

 .51 

 .69 

 .60 

 .57 

 .49 

 .82 

 1.05 



Area 



irrigated 



in ten 



hours. 



Cost per 

 acre each 

 irriga- 

 tion. 



Acre. 

 0.74 

 .66 

 .66 

 .78 

 .65 

 .65 

 .64 

 .57 

 .66 

 .47 

 .49 



Discharge 

 per day. 



$0.80 

 .90 

 .95 

 .74 

 .80 



1.06 

 .94 



1.00 

 .74 



1.74 



2.14 



Acre-foot. 

 0.24 

 .23 

 .24 

 .21 

 .21 

 .20 

 .23 

 .26 

 .20 

 .17 

 .16 



. e Cost per 



^^I^'^^rl\ acre for 



''J^ each foot 

 gated. Qfijfj_ 



Ac 



res. 



10.3 

 8.6 

 8 



9.4 

 7.3 

 7.6 

 7 



6.1 

 7.2 

 5.3 

 4.8 



3.27 

 .18 

 .17 

 .12 

 .10 

 .12 

 .09 

 .08 

 .05 

 .09 

 .09 



THE ARCHIMEDEAN SCREW. 



In the delta a nuiii))ev of unusual methods are employed for raising ■ 

 water from 1 to i or 5 feet. One of the most striking of these, and 

 one the least to be expected in Egypt, is the Archimedean screw. 

 Around an iron shaft some 11 or 15 feet long is built a .screw, made 

 up of thin pieces of wood so fitted together as to be practically water- 

 tight. A water-tight wooden cylinder is constructed around the screw. 

 The diameter of the cylinder is ordinarily about 14 inches, and its 

 length does not often exceed 8 or 9 feet. The pitch of the screw is 

 about 1 revolution to li diameters. The screw is so attached that it 

 will not revolve on the shaft. The shaft projects from both ends of 

 the cylinder and is supported near its extremities by posts. The 

 screw inclines 30 degrees or less to the horizon, with its lower end in 

 the water. To the upper end of the shaft a crank is attached. This 

 lifting device is shown in the accompanying illustration. (PI. XIV.) 

 One or two men usually operate a screw, )>ut in rare cases, when the 

 screw is especially large or the lift considerable, a small engine is 

 employed. High lifts are practically impossible on account of the 

 difficulty of supporting a screw of great length. This device is more 

 efficient than the lifting machines contrived by the natives. One man 

 can irrigate from 1 to 2 acres a day with this machine, provided the 

 lift be not over 2 feet. The efficiency of the Archimedean screw is 

 shown in the following table*. 



Efficiency of the Archimedean screw as a water-raising device. 



Height of Hft. 



3.3 feet 



4.5 feet 



4.6 feet 

 5.1 feet 

 5.9 feet 



Number 

 of men 



working 

 periods 

 of two 

 hours. 



per day. 



Acre- foot. 

 0.47 

 .49 

 ..52 

 .45 

 .41 



Area of 

 field irri- 

 gated. 



Acres. 

 14.2 

 10.8 

 10 

 6.4 

 11.7 



Cost per 



acre for 



each foi't 



of lift. 



$0.08 

 .05 

 .04 

 .06 

 .04 



