Evening star., 1939-10-15

ute as vital to hogs, horses, shcep
I'd chickens. 1t does find an important
ace IN their diet, and that gives 1t
Ii bill of usefulness on almost any
rm.
Until fairly recently, a mixture OF
,ck salt and ice was the only praC-
cal means of obtaining low tenn
eratures for refrigeration, particularly
the refrigerator cars that carried
eat and milk from the farms and
ockyards to distant cities.
Now we have electrical refrigeration
I'd the amazing dry ice; but you II be
tereSted to know that the old rock
llt-and-lCe combination Is attempting
IN a new and better form.
special mixture OF saturated Solu-
on of salt IN water Is frozen on
revolving nickel drums into cx-
tremely thin ribbons that can send
the mercury down to SIX below
zero. Three pounds will cool as
much as one pound of dry ice.
which means that you need more;
but the joker in the matter IS
that three pounds of the new salt
ice costs about one third as much
as pound of dry ice.
You may be already surprised at
the versatility of the humble stuff
in your salt shaker, but it has
many more uses still. 1t is the
source of caustlc soda, hydrogen
and chlorine and because of those
three chemicals, salt is important
to list of things that would keep
you reading all night. Cleaning
fluid, antlfreeze, dyes, lye. paper
and soap lead that list.
1t is the father of chlorine, which
was, on the one hand, the most
important Of the poison gases used
in the last war and, on the other
hand, the chief ingredient of the
famous Carrel-Dakin solution,
which is one of the best and safest
antiseptics known and which saved
hundreds of thousands of lives in
the same war when used to prevent
infections in wounds. And typhoid
fever, which used to sweep over
whole cities in epidemic proper
tons. has been practically stamped
out by the addition of a little
chlorine, among other chemicals,
to the water supply in most cities
and towns Besides that. 1t bleaChes
all of the cloth and most of the
paper we use and finds its way into
the refining of oil to produce
gasoline.
Now, if you've been gradually
working up good case OF nerves
thinking about our whlmsy on all
life coming to an end If salt should
disappear from the earth, you're
worrying needlessly. Although SCI
entists in their lighter moods are
willing to make all sorts OF pre-
diCtions about how long our oil or
coal or platinum will last, none of
them has yet been willing to haz-
ard a guess about salt. As far as
anyone can see, the supply OF 1t
is practically unlimited, there be-
ing an inconcelvable number OF
pounds in the ocean alone.
Right now our salt doesn' come
from the oceans - ocean salt IS too
impure to be profitable - but from
salt mines and salt wells. The salt
wells are comparatively simple.
Water is pumped down to a salt
bed below the surface of the
ground. the salt is dissolved in the
water and the resultant brine Is
pumped up, the water evaporated
and the remaining salt refined.
Salt mines, on the other hand,
are likely to be huge caverns in the
earth, so that in Czarist Russia it
was customary to send criminals
to the salt mines for period of
years; many of them lived out
their sentences right in the NINE.
rarely ever coming above ground.
Even in American mines there are