Evening star., 1942-04-25
Of Stors, Men
And Atoms
Notebook Of Science Progress
In Laboratory, Field
And Study
By Thomas X. Henry.

By Thomas X. Henry.
The clock of history may be turned
back five centuries with the reappearance
of the knight in armor~ on European
bsttlefelds.
His day supposedly ended when the
English archers turned back the mail
clad French horsemen at Agincourt in
I4l5. Dismounted. the steel-incumbered
barons were easy victims for the agile
yeomen. With the development of gun
powder and musketry. srmor became
only useless impediment.
But surgeons of the Royal Society of
Medicine. according to the London cor
respondent of the American Medical
Association, for the past two years have
been urging that there be at least
partial return to suits of mail. Now. ne
reports. tests are being made of a new
type of body armor for troops which is
said to be proof against point blank
revolver fire as we'll as shrapnel and
splinters.
1t is made of a new light metal"
Plates for the chest and abdomen weigh
only two pounds Picked soldiers are
being put through special field training
TO test the armor and find whether
their movements are slowed down.
Firing tests have been carried out with
rife, tommy gun. machine gun and
shrapnel splinters.
WI MA arft al
return to srmor in the form of the
steel helmet. However cumbersome at
first, 1t proved such an efficient pro-
lection that 1t Vas universally adopted
and now. In some form, is part OF the
field equipment of all armies Partial
idea only few steps further
In the last war this was impractical.
Few Of the light metals, including forms
Of steel. Of great tensile power then
were available. Troop movements were
then, to a much larger extent than at
present, on foot so that the extra bur-
den, even If the armor was carried IN
the pack. would have been upendurable.
Now, surgeons of the Royal Society Of
Medicine stress. there is relatively little
marching in campaign. The soldier
Is carried by truck, train or airplane.
At one meeting of the Royal Society
1t was claimed, without the evidence
being presented, that before the war
Hitler had made three attempts to per-
suade an American manufacturer with
patent on . form of light armor to
take q contract for equipping the Ger
man Army.
1t was stressed that armor to protect
against rife bullets need weigh no more
than 20 pounds, and need not be worn
or carried by the soldier except in actual
conflict. Surgeons pointed out that
many fatal wounds are due to splinters
which enter the chest and rip one OF
the great vessels of the heart.
Sir Richard Cruise. noted British
opthalmologist, declared that from so
to 10 per cent of the blindness resulting
from the last war might have been
prevented II helmets had been pro-
vided with proper visors. One was .x.
hibited made of light metal dlralumin-
primarily aluminium with a small inter-
mixture OF copper. magnesium and
manganese.
Matter takes on strange forms under
pressures Of thousands of times the
weight OF the earths atmosphere per
square inch, it is explained by DR.. p. w.
Bridgeman of Harvard University.
In a recent Sigma XII lecture he de-
scribed the techniques by which labora-
tory pressures have been raised from
about 5000 atmospheres. or $1,000
pounds per square inch, to a value of
ABOUT 100000 pounds per square inch.
This is the pressure that would be found
under tower of bricks nearly 1.5OO
miles high. or at a point 1000 miles be-
low the earth's surface. Long before
such a tower could be built to its i'm
mense height it would be crushed by its
own weight. 1t would crush the hard
est rocks on which it might stand.
Even under this enormous pressure
DR.. Bridgeman explained, graphite re-
fused to change to diamond. Probably
no pressure would bring about the
transformation under ordinary temper
atures.
Boiling hot ice was produced at a
much lower pressure. At 10000 times
the pressure OF the atmosphere ice was
produced at temperature of approxi-
mately 375 degrees. This is 1855 degrees
above the ordinary boiling point of
water.
All substances except those of the
simplest internal structure, DR.. Bridge
man explains, undergo sudden changes
at certain temperatures and pressures.
Up to pressure of $4,000 atmospheres
there are seven different kinds of ice.
all OF them except ordinary ice heavier
than water. In the same range there
are II kinds of solid camphor.
All these transformations are reyers-
ible. AS the pressure is lowered the
preceding forms are restored. DR.. Bridge
man has found, however, that two
transformations are not reversible At
grees F. yellow phosphorus is changed
permanently into black form which is
much like graphite in its properties. At
10000 atmospheres and BAT degrees F.
the clear liquid, carbon disulfde is
changed permanently into black solid
The electrical conductivity of sub
stances is changed by pressure, espe-
cially in the case of poor conductors. At
$4,000 atmospheres the conductivity OF
tellurium is 600 times its value at at
mospheric pressures. For good metallic