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POPULAR SCIENCE MONTHLY. 



which lifted the water about sixty feet. Later the wells are a foot in 

 diameter in groups of ten for each pump. The water is forced through 

 steel pipes twenty-four and thirty inches in diameter to a maximum 

 elevation of four hundred feet. From various points ditches are dug 

 which carry the water to every field of the plantation. The photo- 

 graph, Figure 3, shows one of these pumping stations where there are 

 twenty wells, each a foot in diameter. Though the pumps act without 

 cessation, the water never fails; 5,000 acres of land are irrigated from 

 these wells. The water here rises to the height of 22 feet above sea 

 level. 



5. These wells at Ewa are found to be slightly affected by the brine 



Fig. 3. Ewa Plantation Pumping Station. 



of the sea. The natural waters of the island contain .0073 per cent, 

 of salt according to Dr. Walter Maxwell;* Pacific water holds 2.921 

 per cent, of the same. One hundred grains to the gallon of water 

 represents 0.14 per cent. The analyst of the Ewa company found 

 that the chlorine present (sodium chloride) was more abundant in the 

 wells nearest the ocean. At station No. 1 the chlorine amounted to 

 17.61 grains in a gallon. At stations Nos. 2 and 3, farther inland, 

 the chlorine had diminished to 8.18 and 11.97 grains to the gallon. 

 By experiment at several localities it has been found that the salinity 

 increases when the pumping becomes excessive. At Ewa it is stated 

 that vegetation is not at all affected when the number of grains per 

 * ' Lavas and Soils of the Hawaiian Islands,' 1898. 



