MANUFACTURE OF SALT FROM SEA-WATER 47 



is still used by the peoples of southern Europe and 

 South America. Since the food is salted thoroughly 

 when it is prepared for cooking, salt-shakers are 

 seldom seen on the tables. 



But in Great Britain, Germany, France, and the 

 United States, salt of the highest purity, practically 

 free from calcium and magnesium chlorides, is de- 

 manded for household and dairy use. Impure salt 

 always becomes wet in damp weather and clogs a 

 shaker. 



Most of the Oriental peoples have lagged far 

 behind the Occidentals in modern civilization. So 

 it happens that much of the salt produced in the 

 Orient to-day is obtained by methods which are 

 extremely crude, and whose origin dates from pre- 

 historic times. In the Philippine Islands, large areas 

 of sandy lands along the coast, approximately at 

 the level of high tide, are cleared of vegetation and 

 cleaned. The surface of the prepared land is loosened, 

 and water is led in from the sea through canals and 

 sprinkled over the soil, where it rapidly evaporates. 

 This process is repeated four times a day until a 

 quantity of salt has accumulated on the surface. The 

 loose earth, together with the salt, is then scraped 

 into heaps and collected into leaching-vats, where 

 it is leached with sea-water or weak brine until most 

 of the salt has been extracted. The leachings are col- 

 lected in a shallow cement, earthenware, or clay-lined 

 well. The weak brine obtained is poured back over 

 the leaching-vat, and the operation is repeated until 

 it becomes strong, when it is transferred to shallow 

 crystallizing ponds. 



