364 T. S. Hunt on Salts from Sea-water. 
which is kept apart on account of its great purity, and sold ata 
higher price than the rest. In passing from a density of 26° to 
28°°5, sixty per cent more of salt of second quality are depos- 
ited, and from this point to 32° the remaining fifteen per cent 
are obtained, somewhat impure and deliquescent from the mag- 
nesian salts which it contains, but preferred for the salting of 
fish, on account of its tendency to keep them moist. - The aver- 
age price of the salt at the salines is one franc for 100 kilograms 
(220 pounds avoirdupois), while the impost upon it was, unti 
recently, thirty times that sum, and is even now ten franes the 
100 kilograms, 
waters of the Mediterranean contain, according to the 
analysis of Usiglio, about three per cent of common salt, while 
ose of the Atlantic contain from 2°5 to 2°7 per cent. Int 
waters of the Mediterranean there are besides, about 0'8 per cent 
of sulphates and chlorids of calcium, magnesium and potassium. 
The quantity of water which it is necessary to evaporate 1m 
order to obtain a small amount of salt, thus appears to be very 
great, but under favorable circumstances this is a small consider- 
ation, as will appear from the following fact. The saline of 
rre is situated upon a small lake, communicating with the 
ocean, but fed by streams of fresh water, so that while the waters 
of the open sea have a density of 3°°5, those of the lake have 
only 1°5, or scarcely half the strength of sea water. Never- 
theless the advantages of the position offered by the shores of 
the lake for the establishment of a saline, are sufficient to com- 
pecnsie for the deficiency of salt in the water, and to make 
erre one of the most flourishing salines of the south of France. 
The evaporating surfaces here cover 3,300,000 square eit 
equal to 815 English acres; of this area, one-tenth is occup! 
with the salting tables, but with sea-water, where less evapora 
tion is required to bring the brine to the crystallizing par 
one-sixth of the area would be thus occupied. The ous 
of salt annually produced at the saline of Berre is 20,000, 
Kilograms, h 
Owing to the dilution of the water of the lake of Berre, ‘ e 
proportion of salt there manufactured is small, when we consi er 
the area, and compare the produce with that of other salines 
where pure sea-water is evaporated. According to Mr. ba kd 
2,000,000 square metres may yield 20,000,000 kilograms an? 
ally; and Mr. Payen states that the same amount of salt 18 (oe 
duced at Baynas from a superficies of 1,500,000 metres. alt 
cubie metre of sea-water contains about 25 kilograms of wh 
the evaporation required to produce the above amount CO? oe 
ponds to 800,000 cubic metres, equal in the second pom 
given above, to a layer of water 0-40 metre, or 15¢ Eng 
