Evening star., 1951-03-19
Camera Exposures at
800 MiIIionth of Second
EIeetronic Equipment
Photographs Explosions
By Thomas R. Henry

By Thomas R. Henry
Pictures are being taken with expo
sures as brief as 300 millionth of q
tory here.
The equipment was devised and ID
used chiefly for photographing explo-
sions and makes possible recording of
what happens in minute fractions Of
seconds. It splits the instantaneous
into thousands of parts. It also is
planned to use this "electron camera" to
study the behavior of missiles in flight.
The equipment also can be used when
it is necessary, according to the Naval
Ordnance Laboratory report, to take
two or more pictures at the same ir.G
slant. or at predetermined intervals
with extreme accuracy. It can, for ex-
ample, be used to photograph a bullet
in the air and the reading on a dial
at the same instant.
The camera depends on the principle
of the electron stroboscope, a revolu-
tionary new device largely developed
at the laboratory. It stops motion re-
curing at rates up to 100000 second.
Motion stops when the pulse speed Of
tion of the object
Normal Light Conditions.
The principle itself is very compli-
Gated, but the net effect is that it now
is possible to study high-speed phe.
nomena under normal light conditions
out OF doors. Previous equipment de-
pended on high intensity flash bulbs
Synchronized with a camera and re-
quired studies to be carried on in spe-
cially darkened areas. Thus it was
impossible to duplicate natural condi.
tions with precision.
The camera requires an independent
pulse power supply to give the high
voltage necessary for it's operation. A
brighter image is required to produce
photograph than is needed for direct
viewing
The equipment can be used to estab-
llsh the exact speed with which any
recurring motion takes place. Among
the uses being considered are studies
OF the periodic movements of the flame
IN jet engines and of air flow patterns
in wind tunnels.
rapidly spreading cotton fiber dis
ease which may become apparent only
in the finished cloth has just been re-
ported to the American Association for
the Advancement of Science here.
For convenience it has been named
"cavitoma," because of the tendency to
form cavities within the fibers, both be-
fore and after spinning. 1t is reported
by DR.. j. P. Elting of the research de-
partment of the Kendall Mills at Paw
Greek. N. C.
According to this report some of the
best grades Of cotton received by the
mills now are found to contain an abun-
dance of unidentified micro organisms
which destroy cellulose, the major in.
gredient of the fiber. The disease may
cause considerable deterioration during
warehouse storage When the diseased
cotton is woven into fabric weak places
appear, especially after bleaching.
Aected Area Growing.
Records show, DR.. Elting says, that the
area from which the diseased cotton
comes has been increasing constantly for
the past four years. At first only three
small patches appeared on the map Of
South Carolina. Today the mysterious
malady aeffcts four-fifths of the State.
Only a year ago the first traces were
found in cotton from Texas and Cali.
fornia. Previous infections have been
found confined to the surface of the fl.
bers. This disease penetrates the fibers.
1t can be detected. the report says, by
microscopic examination in its early
stages. Fungi, spores and moving bac-
terra can be detected on the outside Of
fibers with thread-like processes reach
ing through the walls. Inside the fiber
walls are extremely small mould-like or.
ganisms, or possibly bacteria.
AS the disease progresses the fiber be.
comes swollen at the site of the infec-
ton. This swelling affects the entire
length and in some cases the fiber is
virtually destroyed.
The scope of the investigation required
is far beyond the resources of any single
industrial laboratory, DR.. Elting says. He
has reported the disease to the Depart.
ment of Agriculture with request for
a national study.