The New York herald., 1921-09-11

scientist may hazard a guess as to the
why OF their being. The industrial
chemist. regarding speculation pleasing
but futile. accepts natures phenomena
and natures gifts unquestioningly.
Round about the plant and for six Or
seven miles out into the country the der
rlcks of the salt wells rear themselves.
and only near at hand one may hear the
steady play of belt and flywheel as the
pump shaft rises and falls, extracting
the brine, sending 1t on to the central
collecting station at the plant
Il A Thousand mmoditfes.
It Is the salt brine that has given rise
TO Midlands chemical industry and a
pant now internationally known. and
I. ON this mysteriously formed fluid
come the essences Of thousand COM
modities-emulsions for Photographic
Iiates, medicines invaluable for their
curative properties, cements and stucco
and floor tiles, chemicals for tanning
and engraving and for perfuming mi
ladys handkerchief. for ypreserving salt
and chloroform. caustic soda and solu
tions for cold storage.
It Is a leap from the manufacture OF
synthetic indigo and dyestuffs to the
making of pistons for gas engines. Yet
the basis of both are borne on the salt
I'll cams rushing through their unseen
caverns.
Attention was first called to the use
OF metallic magnesium pistons. given the
trade name of Dowmetal. during the 500
mile race at Indianapolis Memorial Day,
when Louis Chevrolet, impressed with
taeir lightness and toughness. ordered
them installed in his five entries just
before the race. The winning car, the
third and the ninth bore Dowmetal pi.-
tons.
Their method of manufacture AMI
their special properties are as interest
ing to the layman, driving pleasantly
along the country roads. as to the auto
motive engineer and the mctallurgist.
i. Extraction of Magnesium.
In 1867, when the Government felt
an imperative need for quantities of
magnesium for use in rockets ard flares.
!, the Dow Chemical Company put its corps
OF chemists to work to perfect processes
by which the magnesium IN the brine
might best and most speedily be ex-
tracted and utilized. The nee1s OF the
Government satisfied. the thought came
that virtually the same processes and
equipment might be used TO produce
metal which should be lighter and
stronger than aluminium. especially
adapted to the reciprocating parts of
internal combustion engines. Metallic
magnesium was not unknown. but pre-
vious attempts to produce an alloy with
sufficient mechanical strength had failed.
A long period Of experimentation re-
suited In the production of Dowmetal.
Then came the need for developing a
commercial use.
The making OF motor pfstons seemed
to present the readiest use. and expert
ments along that line early proved salts
factory.
Downetal, II was found. wa of the
color OF aluminium but Of one-third its
weight II could not score or scratch
the cylinders under the most severe tests.
1t possesses great mechanical strength
and toughness, sustaining a pressure of
$4,000 to $4,000 pounds per square inch
and with an impact toughness twice that
Of cast iron.
ITS value for pistons is evident. The
difference between magnetism alloy pis-
tons and those OF the usual steel OF cast
iron is the difference in lifting a bag
OF feathers and the same filled with pigs
of iron.
From forty salt wells, dug to depth
OF about 400 feet, the brine is pumped
TO the central collecting tank. The
brine when analyzed Is found to contain
calcium. sodium, magnesium. strontium.
bronine and chlorine. This particular
analysis is also found in a salt rock
formation In the vicinity of wyandotte
and in q liquid state near Syracuse.
". T.. but with several Of the constitu-
ents missing.
Method OF Extraction.
At the collecting station the magne-
sium bromide is broken up by electro
iysis and the bromine used In the manu-
facture OF medicinal bromides
The next step is the separation OF the
magnesium chloride brine by chemical
treatment and agitation In eleven tanks.
or settling vats. thirty TO eighty feet In
diameter and fourteen to twenty feet in
depth. Willie here the magnesium brine
10 treated with ather chemicals by a Sc
cret and closely guarded process, result
ing in the separation OF the calcium chio-
ride, sodium chloride ana magnesium
chloride liquora The MAGNESIUM chlo-
ride II then pumped to huge condensers
and vacuum pans. where evaporation is
begun After further treatment and
evaporation the hot liquors are run off
into drums and allowed 70 cool. forming
solid mass known as magnesium chlo-
ride fused.
Tho chaIklike substance Is then
broken up and placed In electric fur
naces. which release the chlorine gas
used IN making Observation-Disclosures the
mctasic magnesium. This appears In
the form of greenish-white froth on
the surface Of the kettles and Is quickly
ekmmcf of and melted into bars or
pigs. The addition OF 10 per cent
alloy. also a secret process. to this me-
tallio magnesium results In Dowmetai.
Tho casting Of the pistons. grinding and
nnfsfhng 10 done in the usual ways.
Since the coefficient expansion OF this
magnesium alloy II approximately that
OF aluminium and higher than that Of
cast iron. slight clearance. usually .00e
or an inch. IL allowed for installation.
Pistons OF the material have been run
az high as $4,000 miles under load
that II. under stress and strain eaulva-
lent to that given a piston running night
and day In a motor car going ~ a rate
OF thirty miles m hour. Examined after
this test tho pistons show little effert