Evening star. [volume] (Washington, D.C.) 1854-1972, 1899-02-18
LIQUID HYDROGEN
Is Just About as Cold as Anything
Can Possibly Be.
PROF. DEWAR'S RECENT SUCCESS
Has Obtained the Lowest Temper
ature Ever Recorded.
INSIDE HIS LABORATORY

From The London News
At the Royal Institution Prof. Dewar re-
Gently gave the first Friday evening die
course of this season. His subject. Liquid
Hydrogen" attracted a very large audi
ence.
1t was on. Tuesday. May 10. 1sas that
Prof. Dewar. In the chemical laboratory of
the Royal Institution, succeeded for the
first time in liquefying hydrogen and hell
UNI, the only two gases which had up tn
then resisted all attempts made by chem
lists TO render them liquid and to change
them from the gaseous 10 the liquid state.
Some Of the textbooks state that certain
investigators have indeed accomplished the
liquefaction of hydrogen. All that these
have seen. however. was a momentary mist
inside glass tube. which they took TO be
the long-sought-for liquid Prof. Dewar has
produced the liquefed gas in quite appre-
ciab.e quantities, and has thus been abba
10 Investigate its properties
Before dealing further with the hquefac-
ton OF hydrogen IL may perhaps be OF in
terest to glance at the scale of low tenn
peratures One might be apt to think that
the coolest temperature on the globe would
b. found at the poles, but this Is not the
case, for here the water circulation tends
TO bring heat from the equator. The aver
age winter temperature or the arctic re-
gions seldom goes lower than ~ degrees
below zero on the Fahrenheit therInometar
In "Farthest North" Nausen mentions that
greatly exaggerated reports OF the arctic
Geld are in circulation. According 10 him.
the general day temperature was about ~
or 43 degrees Fahrenheit below zero Il
was clothed yesterday. he writes, las
usual as regards the leg drawers knicker-
bcckers, stockings, friezs leggins, snow
socks and moccasins; my body covering
consisted of an ordinary shirt. a wolfskin
cape, and a sealskin jacket, and | sweated
like horse. Today l sat still, driving
with only thin ducks above my ordinary
leg wear, and on my body wooden shirt
vest, Iceland wooden Jersey, frieze coat and
a sealskin one. / found the temperature,
quite pleasant, and even perspired a little
today, too. This is easy to understand IL
We remember that dry cold is more easily
borne than a damp one, and that Nansen
was pretty well Injured 10 the sens ations Of
the northern lands.
Cold Place.
The coolest place in the world is werko-
jansk. In January the mean temperature
there is 30 degrees Fahrenheit below zero,
while all the year through the thermometer
never rises beyond degrees above zero.
Probably the greatest cold ever realized -,y
man is 81 degrees Fahrenheit below gro
During an arctic expedition Capt Mares
once saw his thermometer descend Z luis
very low point, and he was doubtless glad
enough to see it get back to the FORMAL
again.
The temperatures with which we are deal
ing IN this article are, will be sect. far
below the greatest cold ever experienced on
the earth. At 229 degrees f. below zero the
gas oxygen is reduced TO a LIQUID: at 3es
degrees the air Of our atmosphere changes
from an invisible gas into a visible and
easily handled liquid. while at $40 degrees
air becomes frozen solid resembling a
mass of ice. Going down still lower on the
Fahrenheit scale We find that the critical
point of hydrogen is :B91 degrees: that Is
to say, until this temperature is reached
no amount of pressure win reduce the gas
to the liquid state The boiling point of the
liquid is probably about 40 +. The zero
of absolute temperature is 46l f., or 273
degrees on the centigrade scale A gas
loses 1918 of its volume for every degree to
which its temperature is lowered Thus at
2I3 degrees below freezing point the volume
of gas would be reduced to nothing.
Measuring Low Temperatures.
Whether the chemist will ever reach this
extreme limit of cold is very doubtful for
it is not easy to see how it is to be at
tanned, for point has been reached beyond
which no appliances of modern science are
of any avail Up to the point where by
drogen becomes liquid the platinum re-
sistance thermometer was the only variety
of thermometer that was Of any service in
enabling Prof. Dewar TO tell what were the
temperatures at which he was working.
The professor now tells US that the plati-
mum resistance thermometer has reached
the limit of its usefulness. If its powers of
registering low temperatures were limitless
then ii would indicate the temperatures at
which liquid hydrogen boiled under differ
ent diminished pressure, but as matter OF
fact its resistance only Indicated diminu-
ton of degree c. in temperature when the
hydrogen was boiling away at one-inch
pressure.
In 1879 Faraday, in the laboratory Of the
Royal Institution. liquefied gas (chlOrineD
for the first time in the annals Of science.
Seventy-five years afterward Prof Dewar,
working in the same laboratory, succeeded
i'm reducing to liquids hydrogen and helium.
the two gases to hold out against the on
slauehts of modern chemistry. The appa-
ratus used in the Royal Institution today
differs very greatly from that used by
Faraday.
An Unusual Laboratory.
Prof. Dewar's chemical laboratory has
been compared TO the engine room of an
Atlantic liner. and. indeed. il does not come
up to ones ideas as to the workshop Of a
chemist. Here are TO be found gas engines,
huge compressors. pumps, belts, shafting
and whole host of engineering appliances.
For every gas there is a critical Temporal
ture, and when the gas is above the tenn
perature no amount of compression can re-
duce it to a liquid. The first step then is to
get the gas down to the required tempera-
ture. When this is done IL is compressed
until it assumes the liquid state. On May
10 an experiment was started with hydro
gen cooled to 205 degrees centigrade, and
continuously under a pressure of
$50 degrees atmosphere from the nozzle of
the coil of pipe a the rate of 10 to Is cubic
feet minute In a vacuum vessel, doubly
silvered, of special construction, surround
ed with space kept below 200 degrees GEN.
Upgrade. With these arrangements LIQUID
hydrogen began to drop from this vacuum
vessel into another, doubly isolated by be-
Ing Enclosed within third coli, and i'm FIVE
minutes twenty cubic centimeters of liquid
were collected. In its liquid condition ny
drogen is clear and colorless, looking for
all the world like water, except that il
boils away at this exceedingly low tem<
lowest that man has ever
reached.
Practical Uses.
Prof. Dewar has shown how liquid hydro
gen can be used as a condensing agent for :.
the production OF very high vacua, the
contents of closed tube containing air be-
ing quickly condensed as solid air when one
end of the tube was immersed in the liquid.
When the portion of the tube from which
The air had thus been removed by cOnden-