Evening star., 1950-03-01
Time Measure Reported
In BiIIionths of Seconds
Yale Scientists Studies
To Aid NucIeur Work
By Thomas r. Henry

10 Aid Nucleor Work
By Thomas X. Henry
The finest time measurements ever
made have just been reported to the
Once of Naval Research here.
They are in billionths of seconds-or
millimicroseconds- are Of at least
ten-fold briefer intervals than ever have
been claimed before.
The extreme minuteness has been
achieved by Drs. Ernest G. Pollard and
w. L. Schultz Of Yale, working on .
naval project.
A pair Of nuclear particle counters. Of
the general type Of Geiger counters, are
set up. They are attached to amplifiers.
The impulses from these amplifiers then
are picked up by a transformer which
changes them into pulses of electricity.
If they arrive at precisely the same
time. the voltage Of this pulse is exactly
twice as great as would be the case for
one alone. If there is any delay In the
arrival Of one Of the impulses ut the
transformer, the current Is reduced. This
difference can be measured with exacti-
tude.
The method measures time differences
OF two or three billionths Of . second,
the Yale physicists claim.
Aid to Nuclear Studies.
Such fine time measurements are ex-
pected to prove of considerable value in
studies Of the atomic nucleus. the only
place where events happen at such
speeds. It has been recognized for some
time, for example. that one type of
radioactive gold produced in uranium
piles changes into the extremely rare
element holmium, one of the rare earths.
BY the new method it has been deter
mined that the actual time required for
the transformation is approximately
twenty millimicroseconds.
Another fine measurement accom-
plished at Yale is of the lifetime Of
the positron. or positive electron, which
Is one Of the most important Of nuclear
particles for any understanding Of the
processes Of nuclear physics. It is an
initiated almost simultaneously with its
coming into existence. BY the new
method its lifetime has been determined
at about Is millimicroseconds.
There also may be use for the method
in measuring with greater accuracy rela-
lively long periods in atomic phenomena
such as the millionths Of seconds re-
quired for the disintegration Of mesons.
It has been possible to- estimate these
before with considerable accuracy but
the estimates now can be replaced with
precise measurements.
A booster" which considerably IN
creases the effect Of streptomycin on
tuberculosis has been reported by United
States Public Health Service scientists.
It may make possible achieving the
same effects with considerably smaller
doses.
The booster" is . substance known
Is usnic acid. Some claims have been
made that this acid, per se. Is mildly
effective against the tubercle bacillus.
Experiments with guinea pigs innocu-
lated with Q particularly virulent strain
showed these claims apparently have no
foundation, report Drs. Alfred Marshak
and Marvin Kuschner, working at New
York University Medical Center.
When usnic acid and streptomycin
were combined. however. the effects
were quite striking. The general theory
advanced is that each drug attacks
. particular part Of the tubercle bacillus
system. The damage done by usnic acid
is not necessarily lethal, but the work
of the streptomycin is made easier.
Germs Acquire Resistance.
The promise Of streptomycin as
tuberculosis remedy has been clouded
considerably by the fact that the germs
acquire an increasing resistance to 1t.
eventually reaching the point where
they hardly can live without 1t. Higher
and higher doses are required until they
reach = severely poisonous level. II the
initial dosage can be materially de-
creased with the same effects. . notable
gain will have been achieved.
Various combinations have been tested.
usually between streptomycin and some
other drug which has shown a marked
effect against tuberculosis. Most such
drugs have turned out to be highly
poisonous so that they can be used in
human treatment only with extreme
caution; and results to date have not
been too promising.
Usnic acid itself is quite poisonous to
guinea pigs. and probably to man. A
new problem Of adequate balance is
posed 50 that the therapeutic effect
will be greater than the poisoning eff
feet.