Evening star. [volume] (Washington, D.C.) 1854-1972, 1929-07-07

passed along this conundrum OF scientific
identification recently to DR.. Clark. Forth
with the scientist made simultaneous X-ray
pictures Of specimen Of the waxed paper and
. sample Of ordinary paper treated with pow.
dered copper. BY direct comparison Of the
x-ray pictures he ascertained that the i'm.
purities on the wax paper were not copper.
Elimination thus proved that they were brass.
The manufacturer was then enabled to modify
manufacturing processes to eradicate the brass
specks
Another riddle which DR.. Clark solved fea-
tured thorough examination Of the steel
used in the manufacture Of transformers. The
size Of the steel crystals depends largely on the
heat treatment to which the steel is subjected.
If molten steel is cooled suddenly, exceed
tngly small crystals are formed, while If the
metal is annealed carefully the resultant crys-
tails are much larger. The x-ray pictures
enabled the scientist to predict accurately the
adaptability of different steels for electrical
manufacturing purposes.
Key metals essential in industry can be
X-rayed and diagnosed faithfully as to freedom
from flaws and strains which would incauaci-
tate them for vital industrial uses. It usually
takes from 36 to 48 hours to X-ray q specimen
Of steel one millimeter in thickness. which is
exposed to the pinhole beam of the molyb-
denum X-ray. This molybdenum target ma
chine gives X-rays of double the penetrating
power OF the ordinary research machine
equipped with copper target.
ONE Of the important applications of radiog-
raphy or shadow work to industry is the
study OF metal YIELDS to demonstrate that they
are free of cracks, faults and flaws. If any
such defect occurs In weld the X-ray win.
nnd and reproduce the point Of weakness AZ a
plack streak on the negative. Even invisible
defects in false teeth are disclosed before the
an-revealng eyes of x-ray wizardy.
Castings provide another extensive field fc9
Pathological inspection, as accurate determine.
lions can be made of the strength and durabil-.
ity OF such parts Industry would save millions,
IN money and thousands of lives II all the
critical castings used for vital purposes were
standardized by x-ray examination and Ger.
uncation previous to service use
Inc service life OF some such eouipment
as water-power turbine, exposed to severe
STRAIN and pressure, can now be predicted ac-
curately where it is x-rayed previous to install
iatlon Such scientific inspection not only aids
the procurement of the strongest and best
equipment adapted for special work. but IL
also SHOWS how long such a machine will be
SerVlceaole. Furthermore, X-ray revelations
transcribed as aids to industry indicate exactav
how much castings and forgings may be re-
duced In size without impairing their mar
gins of safety for various uses.
For generations various trades and indus
tries nave believed implicitly that forginRs
were generally free from internal blemishes.
recent A-ray pictures have proved the fallacy
OF such beliefs. 1t is only matter of time
until industry will X-ray all forgings for vital
t tuuuS'tlai purposes. The strength and dura-
niilty OF rolled sheet steel and drawn wire can
De determined definitely in similar way-facts
previously unobtainable.
Inis information is important, as the prop
erueS OF metals are changed radically by SUCH
mechanical manipulations