VOL. XLV.J PHILOSOPHICAL TRANSACTIONS. 521 



water, or the salt water of wells, fountains, lakes, or rivers; or water of any 

 sort impregnated with rock salt, or other kinds of common salt. 



The first of these kinds of salt is in several countries found so pure, that it 

 serves for most domestic uses, without any previous preparation, triture excepted. 

 But the English fossil salt is unfit for the uses of the kitchen, till by solution 

 and coction it is freed from several impurities, and reduced to white salt. The 

 British white salt also is not so proper as several kinds of bay-salt for curing fish, 

 and such flesh-meats as are intended for sea provisions, or for exportation into 

 hot countries. So that, for these purposes, we are obliged, either wholly or in 

 part, to use bay-salt, which we purchase in France, Spain, and other foreign 

 countries. 



Bay-salt in general may be divided into two kinds. First, bay-salt, drawn 

 from sea-water, as is practised in France, Spain, Portugal, and many other 

 countries. Secondly, bay-salt extracted from salt springs, ponds, and lakes; as 

 at Cape de Verd islands, Tortuga, and other places. Of these the first is im- 

 ported in large quantities into Great Britain and Ireland; our American colonies, 

 in times of peace, are chiefly supplied with the latter; but in time of war they 

 have large quantities of bay-salt from Lisbon, and other parts of Portugal, 



Bay-salt is prepared in a manner the most simple and easy, when the water of 

 ponds and lakes impregnated with salt is totally exhaled by the force of the sun 

 and air, and the salt is left concreted into a hard crust at the bottom of the 

 lake or pond. Of salt thus prepared, we have instances in many parts of the 

 world; as in the Podolian desert near the river Borysthenes on the Russian fron- 

 tiers towards Crim Tartary, in the kingdom of Algiers, and in other parts of the 

 world. Bay-salt is also drawn from the brine of ponds and lakes, and our author 

 gives an account of the preparing it in this manner in the Cape de Verd islands. 

 He also takes notice of the bay-salt made at Tortuga, and other places in Ame- 

 rica. He describes likewise the manner of making marine bay-salt in France, 

 and other parts of Europe. Every kind of bay-salt is prepared without artificial 

 heat, and by only exposing the brine under a large surface to the action of the 

 sun and air, by which, in proportion to the strength of the brine, and to the 

 different temperature of climate and season, the salt crystallizes into what we 

 call bay-salt, and comes under different appearances to us from different places, 

 which arise principally from the cleanliness and care of the artist. 



Our author, when treating of white salt in general, acquaints us, that though 

 salt is made, in warm climates, with the greatest ease, and at the least expence, 

 by the heat of the sun, after the methods already described ; yet, in several 

 countries, where bay-salt might be conveniently made, they prepare all their salt 

 by culinary fires. Thus in Austria, Bavaria, and many other parts of Germany, 

 and also in Hungaiy, and even in some parts of Italy, they constantly boil the 



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