50 THE WEALTH OF THE SEA 



given area of land depends upon the rate of evapo- 

 ration and the amount of rainfall during the salt- 

 making season. Since the rate of evaporation usually 

 is rather low, a large area of evaporation ponds is 

 required to produce a comparatively small quantity 

 of salt. 



Salines are found along the coasts of southern 

 France, Spain, Portugal, and Italy wherever there 

 are suitable areas of low-lying land. The salt gardens, 

 as they are called, are very picturesque with their 

 succession of reservoirs, old-fashioned windmills, 

 and piles of glistening white salt. Many of them 

 have been operated continuously for several centu- 

 ries. 



Southern Europe produces an enormous quantity 

 of solar sea-salt. The salines of Trapani alone 

 yielded 300,000 tons in 1922. Sicilian solar salt is 

 bought largely by the Scandinavians, who use it in 

 the preservation of fish. Trapani and Iviza ship 

 large quantities of salt to America, where it is used 

 principally in the curing of cod, haddock, herring, 

 and other fish. In the construction of these salt 

 works, low-lying flats are inclosed by high dikes to 

 prevent flooding by high tides or storms. Each salt 

 meadow or "garden" is subdivided into several ponds 

 of different levels, connected by canals through 

 which the brine may be run from one pond to the 

 next. 



The first pond in the system, the concentration 

 reservoir, is large and deep, and usually at a higher 

 level than any of the subsequent ponds^ so that the 

 brine may be run by gravity to the other ponds. 



