LAND RECLAMATION. 193 



metres on a mean lift of 3*02 metres using per million 

 metres 19 tons of coal costing L.E. 1*746 per ton. At 

 Atfeh the cost is increased by charging maintenance and 

 staff though pumping only 36 days in the year. 



There are many large pumping stations for the drainage 

 of low lands and marshes in England, Holland, Italy, 

 France and elsewhere and steam-driven centrifugal pumps 

 have displaced scoop wheels and Archimedean screws 

 driven either by steam engines or wind-mills. There has 

 recently been installed in Upper Egypt a pumping station 

 which, by the use of Green's Economiser and superheated 

 steam, is said to have reduced coal consumption to 2 J Ibs. 

 per water horse -power per hour. In reclamation works 

 dependent on pumping there is this difficulty, that at first 

 the length of drain made does not afford reservoir capacity 

 to allow intermittent action of the pumps. If the pumps 

 evacuate water more quickly than the drains bring it to 

 the sump, the latter is rapidly lowered and the pumps are 

 working on a high lift and have to be stopped before land 

 at a distance at say 10 miles begins to feel the effect. 

 Then if the drains convey more water than the pumps can 

 lift their level rises at the sump end. Centrifugal pumps 

 to work economically must run at a certain speed, lifting 

 a fixed quantity of water, and it is impossible to regulate 

 drainage so that exactly this quantity is brought to the 

 pumps and a fixed level maintained in the drains. In 

 reclamation works of any size, where the quantity of 

 drainage varies at different seasons of the year, there should 

 be at least two if not three pumps, so that one or two 

 or all three may be worked as required at full capacity. 

 As reclamation proceeds, more drains are made, till their 



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