Evening star. [volume] (Washington, D.C.) 1854-1972, 1927-03-27

Radio and telephone are multiply
ing the uses of vacuum tubes, ana
the nations bill for glass-contained
vacua now exceeds a million dollars
a week, according to a research re-
port to the Engineering Foundation
by DIR. w. r. Whitney, director of
the research laboratory of the Gen
eral Electric Co., Schenectady.
Science, it is pointed out, has SO
far failed to obtain complete
vacuum. Materially, there are count
less thousands >of molecules in the
highest vacuum attained.
Strive as they may, scientists
have been unable to attain a vacuum
wherein a cubic inch includes fewer
molecules than there are people in
the world" says the report. Even
so, they have succeeded in removing
80 99999999 per cent of the gas.
"In other words, only one of every
&c, 0OO, 900 900 molecules remains. Yet
there are DC, 900 ,000, 900 molecules in
every cubic inch. The population
of the earth is estimated at less than
1000, 900 900.
Across the broad girth Of America,
from New York to San Francisco,
four days journey by train, 80 hours
by swiftest airplane, imagine a great
belt of fine sand a thousand feet, or
nearly a fifth of a mile, in width and
10 feet deep.
Its length. from coast to coast,
would be more than $500 miles. Then
imagine it suddenly reduced to line,
so slender as to be almost invisible,
lust two grains broad and one grain
deep.
THAT is a graphic illustration of
how completely modern Coolidge
X-ray tube is exhausted of air by the
high efficiency Langmuir condensa-
ton pump in the research laboratory
of the General Electric Co.
1.-THE great beach with its millions
of millions of grains of sand is SYM
bolic of the cubic inch of air at atmos-
pheric pressure, IL each of its molecules
were enlarged to the size of grain
of sand one one-hundredth of an inch
in diameter, and the line two grains
broad and one grain deep represents
the almost complete vacuum obtain
able with the Langmuir pump. No
vacuum known to science is abso-
lutely complete.
THE swiftness with which the air is
drawn out is equally marvellous. II,
from a vessel holding a quart, there
were removed a million molecules q
second, it would take $50 100000 years
to remove practically all of its air, but
the Langmuir pump accomplishes
this in just two seconds.
Ability to create even partial vacua
in inclosed spaces has been Of great
use. 1t has made possible suction
pumps, thermometers, incandescent
electric lamps and many improved
physical and chemical processes, and
has increased the efficiency of steam
engines and turbines
AT night we see largely by the aid Of
vacuum lamps. BY means of other
vacuum lamps (x-ray tubes) we can
also see through Opaque bodies. Our
transcontinental wired telephony is
possible through vacuum tubes,
which, in various forms, also permit
our radio broadcasting and radio re-
ception from the most remote stations.
zone of the latest achievements of
science, the transmission of photo
graphs by wire or wireless, incorpor-
ate still another vacuum tube, the
photo-electric cell.
THE workman who keeps his drink
hot or cold in a thermos boeale Is in
debted to Sir James Dewar's appli-
cation of the vacuum, but the scientist
is still more indebted to 1t. Our steam
power plants, including turbines, also
owe their success to vacua.
"Vacua are Of different type. For
the steam turbine, rough vacuum is
sufficient-about an inch of mercury,
Incandescent lamps formerly required
the. best vacua available, but there are
now other commercial vacua neces-
sarily quite superior, such as those
for X.ray and radio tubes, and for the
newly developed cathode ray tubes.
$50 much for vacua within inclosed
spaces on our planet We have reached
the point where only one of ten billion
molecules remains In as perfect
vacuum as we have attained, but has
far outdistanced us.
at appears evident, or at least prob
able, that the condition which humans
call vacuum is the natural state
throughout the vastness of interested
lar space, and some of the stars-mil-
lions Of miles in diameter and count
less millions Of miles away from us
are but superheated gases, less dense
than the residual gas In the most near
ly perfect vacuum tube we know"