54 



Buttresses 3.75 feet thick and 26 feet wide are located ])etween each 

 set of 10 shiicewavs, or a)>out 2-1:0 feet apart. The l)uttres.ses were 

 added rather for the sake of appearance than to increase the strength 

 of the wall. The four locks at the western end of the dam are each 

 200 feet long- and 81 feet wide. They will enable small boats to pass 

 at nearlj- any time during- the year. 



Fig. 9.— Details of apparatus for raising gates, Assnan dam 



There are 180 sluiceways through the dam. Of these 65 have been 

 placed with their sills practically on a level with the bed of the river. 

 Forty of these low sluiceways are lined with cast iron (PI. XXII. tig. 1), 

 all others being lined with ashlar masonry. The cast iron is not con- 

 sidered as durable as the granite, but by employing it the work was 

 much hastened, so that the sluiceways connucnced at the end of one 



