500 PLINTHS ffATimAL HISTORY. [Book XXXI. 



CHIP. 39. (7.) THE VARIOUS KINDS OF SALT ; THE METHODS OF 



PREPARING IT, AND THE REMEDIES DERIVED FROM IT. TWO 

 HUNDRED AND FOUR OBSERVATIONS THEREUPON. 



All salt is either native or artificial ; 84 both kinds being 

 formed in various ways, but produced from one of these two 

 causes, the condensation or the desiccation, of a liquid. 85 The 

 Lake of Tarentum is dried up by the heat of the summer sun, 

 and the whole of its waters, which are at no time very deep, 

 not higher than the knee in fact, are changed into one mass 

 of salt. The same, too, with a lake in Sicily, Cocanicus by 

 name, and another in the vicinity of Gela. But in the case of 

 these two last, it is only the sides 86 that are thus dried up ; 

 whereas in Phrygia, in Cappadocia, and at Aspendus, where 

 the same phenomena are observable, the water is dried up to 

 a much larger extent, to the very middle of the lake, in fact. 

 There is also another marvellous 87 circumstance connected with 

 this last -however much salt is taken out of it in the day, its 

 place is supplied again during the night. Every kind of lake- 

 salt is found in grains, and not in the form of blocks. 88 



Sea- water, again, spontaneously produces another kind of 

 salt, from the foam which it leaves on shore at high-water 

 mark, or adhering to rocks; this being, in all cases, condensed 

 by the action of the sun, and that 89 salt being the most pun- 

 gent of the two which is found upon the rocks. 



There are also three diiferent kinds of native salt. In Bac- 

 triana there are two vast lakes ; 80 one of them situate on the side 



84 " Sal fit." This expression is not correct, there being no such thing 

 as made salt. It is only collected from a state of suspension or dissolution. 

 Pliny, however, includes under the name kt sal" many substances, which 

 in reality are not salt. His " hammoniacum," for instance, if identical 

 with hydrocblorate of ammonia, can with justice be said to be made, being 

 formed artificially from other substances. 



85 " Coacto humore vel siccato." These two terms in reality imply the 

 same process, by the medium of evaporation ; the former perfect, the latter 

 imperfect. 



h6 The evaporation not being sufficiently strong to dry up the deeper parts. 



87 There is in reality nothing wonderful in this, considering that most 

 lakes are constantly fed with the streams of rivers, which carry mineral salts 

 along with them, and that the work of evaporation is always going on. 



S8 " Glsebas." 



89 Because it is necessarily purer than that found upon the sand. 



90 The description is not sufficiently clear to enable us to identify these 

 lakes with certainty. Ajasson thinks that one of them may be the Lake 



