The Wilmington daily Republican. (Wilmington, Del.) 1890-1902, 1899-06-19
THE MAKING or SALT.
ANCIENT AND MODERN SYSTEMS or
49,, REDUCING BRINE.

NSb0SlN0 0VINss
TAe Methods Used Include Solar
Evaporation, Kettles and Open and
Vacuum Pans-salt beds of Amefl-
ca and Their Ancient Origin.
There are two general sources from
which salt Is obtained, natural brines
and solid deposits. A number Of theories
have been advanced to account for the
latter. The general impression among
scientific men is that rock salt has been
formed by evaporation from ancient seas,
which had become inclosed in some way.
In confirmation Of this notion it is point
ed out that deposits are being made to-
day at the bottom of several well known
salt lakes. But doubts have been ex-
pressed a. to the applicability of the ex-
plantation to such thick strata as those at
stassfurt, Germany, 1890 feet deep,
aud At spetenbers, near Berlin, $500
feet thick. However this may be, the
substance rs found. in greater or less
purity, in all parts OF the world. The min
erals associated with it are those which
are apt to exist In the ocean. What Is
commonly known as Salt is principally
chloride Of sodium. But chlorides Of
lime and magnesium, sulphates of lime
and magnesium and even minute guam
titles Of iodides and bromides are usually
mingled with the chief constituent.
For long time Turks island, In the
West indies, was a copious contributor to
this country's supply of rock salt. But a
number Of mines are now being worked
in the United States. The most famous
at present arc those at Livonia, N. Y.
The salt Is taken out in solid chunks,
ground, passed through sleeves Of differ
ing mesh-to be graded according to
coarseness-and put up in bags or bar
rels. There Is famous deposit In Lou
isiana much nearer the surface of the
ground and more easily worked, which
will be an important producer some day.
There are many salt deposits in this
country which are made available, not
by mining, but by the pumping Of brine
from their vicinity. Through large
part of Michigan, for instance, and from
the central part Of New York state out
as far as Buffalo, there are beds varying
in thickness from 112 to 800 feet and ly-
ing from 600 to 1900 feet below the sur
face. All through these two regions, as
well as in northern Ohio, wells have been
sunk, and the brine Is pumped up like
oil. Fresh water springs supply the wa
ter, no doubt, and this, flowing over and
through the solid salt, dissolves the lat
ter and puts it within mans reach. In a
few places there are salt springs which
eject their mineral laden fluids without
coaxing.
There are five principle methods Of
treating brines in order to get the salt
from them. One of the oldest systems
is that SO extensively employed at SYRIA
cuse. The brine is poured into enormous,
shallow, wooden watts and exposed to the
sun and wind to dry Whenever there Is
a rainstorm. covers are drawn over them
to exclude additional water Precautions
are also taken against the admission of
dirt. The product obtained in this way
is called ''solar salt" Owing to the slow
ness of the evaporative process the
grains thus formed are coarse.
To hasten matters artificial heat is Of
ten used. For instance, rows of kettles
are arranged SO that coal fires may be
maintained under them. As the water
bois off the salt crystallzes in the bot
tom of the receptacle. BY regulating the
degree of heat applied and providing for
marked differences Of temperature in two
sets Of kettles, grains Of different sizes
l,, bo roc,,ltipr
from the more rapid evaporation. This
method is an ancient one.
In Wyoming county, N. Y, artificial
heat is used in another way. Metal pans
about 1875 feet long, % feet wide and
perhaps 211a feet deep, are warmed by
furnaces directly under them. Coal is
used in the latter. The heat being ap.
piled directly, the system is known as
the direct heat" plan. 1t is further
characteristic of the process that it is
conducted with open pans. An indirect
mode Of bringing the heat to bear on the
brine is to line the watts, which are small.
er receptacles than those just described,
with steam pipes, which run around the
inner edge of the same and transmit
their heat to the fluid The indirect heat
upHuIdluS Is Cdlleu SluiAtl.
Finally it has been found feasible to
save fuel and obtain purer salt by in
closing the brine in tight vessel from
which the air has been almost entirely
exhausted. This is called a vacuum
PAN" 1t is a well known fact that eyap-
GRAFTON takes place at lower tempera-
turc when the air pressure is reduced
than at ordinary pressurcs. This is the
reason why water boils at lower TEN.
peraturc on mountain top than on
plain. In the vacuum pan the work can
be done by heating the brine to only 1l2
degrees. The product Of the vacuum pan
process is n beautiful article and COM
mands higher price than other salts.
The grains form in cubes instead of
flakes. The salt obtained from the indi-
rect heat (steam pipe system is also Of
an excellent quality.
Salt had been obtained from sea water
in many parts of the world. Owing to
the foulncss Of the drainage into the
ocean from the land it is desirable to be
particular about the source of supply.
Moreover, there are regions in the trop-
les where the salinity of the water is
greater than it is in older climates and
where the same amount of labor will
yield a larger quantity Of solids. The in
dustry is carried on, however, in a mod
est way on Cape Cod and in Bristol,
Mass. A more considerable business is
done in San Francisco bay, in the county
Of Alameda. From 25 to 80 establish
ments are in operation in that part Of
the country. Other factories for getting
salt from the sea are situated in Los
Angeles and San Diego.
The salt beds Of America are found in
various geological formations. Those of
western New York, northern Ohio and
some parts of Michigan represent the
sluriun period, when the earliest forms
of animal life made their appearance.
The deposits near East Saginaw, Mich,
belong to the carboniferous age, which is
much later. The Kansas beds are placed
in the triassic series by Professor Robert
Hay, and some of the Virginia wells tap
tertiary rocks. From the taste of the
ocean Of today it is apparent that good
deal of salt is still left undeposted. The
work of qualification and storage mas
been going on, then, more or less inter-
mittently for an almost incalculable peri
cd and yet is not fnished.-New York
Tribune.