500 
PLINY*S NATUBAL HISTORY. [Book XXXI. 
CHAP. 39. (7.) THE VAKIOUS KINDS OF SALT ; THE METHODS OF 
PREPARmG IT, AND THE REMPJDIES DERIVED FROM IT. TWO 
HUNDRED AND FOUR OBSERVATIONS THEREUPON. 
All salt is either native or artificial both kinds being 
formed in various wa^^s, but produced from one of these two 
causes, the condensation or the desiccation, of a liquid. 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 
i these two last, it is only the ^des^^ that are thus dried up ; 
whereas in Phrygia, in Cappadocia, and at Aspendus, where 
the same phaenomena 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^^ 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.^^ 
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^^ salt being the most pun- 
gent of the two which is found upon the rocks. 
There are also three different kinds of native salt. In Bac- 
triana there are two vast lakes ; one of them situate on the side 
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 "sal'* many substances, which 
in reality are not salt. His hammoniacum,*' for instance, if identical 
with hydrochlorate of ammonia, can with justice be said to be made^ being 
formed artificially from other substances. 
" Coacto humore vel siccato." These two terras in reality imply the 
game process, by the medium of evaporation ; the former perfect, the latter 
imperfect. 
The evaporation not being sufficiently strong to dry up the deeper parts. 
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. 
Glsebas." 
Because it is necessarily purer than that found upon the sand. 
9^ 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 
