Evening star., 1937-08-05
STARS, MEN AND ATOMS
Notebook of Science Progress in Field,
Laboratory and Study.
BY THOMAS r. HENRY.

Stuff costing ten million dollars an
ounce can't be wasted.
That is a conservative estimate of the
cost of some newly discovered vitamins
and hormones in pure state, DR.. A. H.
Corwin of Johns Hopkins University
stresses in report to the American
Chemical Society. Compared with them,
radium, priced at about $850,000 an
ounce, is dirt cheap.
Such extraordinary values have made
1t necessary to develop chemical meth
ods for detecting the tiniest speck, DR..
Corwin said. The chief Of these is the
microchemical balance whose unit Of
weight is about one twenty fifth mil
lionth of an ounce-or one gamma. This
is about the weight of q dust particle.
This very fact makes much further re-
finement impossible, DR.. Corwin said,
because dust particles occasionally will
settle on the best protected instruments.
Micro-balances, he said, are so sensi-
tive that many disturbing factors other
than dust can render their readings un-
reliable. A vibration from a passing
automobile or subway train can effect
the balance seriously. The animal heat
from the body of the operator or from
visitors to room may be recorded as
weight.
"One company" said Dr. Corwin, was
so naive as to advertise that it had q
balance sensitive enough to weigh a
beam of light. But scientist desiring
to weigh hormone does not want to
weigh beams of light. If thermometer
jumped ten degrees every time you
turned on the radio you would not place
much reliance on it as an instrument for
measuring temperature. In the same
way balance which will record heat,
light or the vibration of passing auto
mobile is not very reliable instrument
for measuring weights.
If, on the other hand, it were necessary
to install every micro balance in dark,
aforementioned room with all dust ex-
cluded and the temperature carefully
regulated, and if the chemist could only
read the instrument through a telescope
from distance, the device would not be
practical to use in his work.
The present objective, DR.. CorWin
stressed, is to get an instrument that
will weigh accurately one gamma under
laboratory conditions. In order to re-
duce the friction of the movable balance
parts scientists have studied methods for
producing sharp knives. Knives have
been prepared so sharp that the finest
microscope is unable to detect their
width. These knives, DR.. Corwin said,
constitute the closest approach known
to the mathematical line which has
length but no width. This is necessarily
an abstraction in the world of reality.
But these knives acted like cylinders
large enough to see under a microscope
during the actual process of weighing.
This effect was due, 1t was found, to
the reformation OF the knife by the
weight of the tiny balance. Said DR..
Corwin:
Just as there is no such thing as an
irresistible force, so there is no such thing
as an immovable body. The hardest
substances known to man are deformed
by the weight of these tiny balances just
as rubber tire gives under the weight
of the machine. The reformation Is not
large, but by proper manipulation these
balances may be used as instruments to
measure the amount that sapphire or
a diamond would be squashed by the
weight of a dime. In order to protect
these delicate knives from injury while
the objects on the balance are being
changed It Is necessary to separate them
from the hat bearings On which they