The morning news. [volume] (Savannah, Ga.) 1887-1900, 1899-06-21
LIQUID HYDROGEN.
Some Experiments Made by Profess
SOr Dewar-It Freezes the AIR.

SOr Dewar-It Freezes the Air.
From the London Times.
The second lecture in connection with the
celebration Of the Royal Institutions CEN
tenary was given sast night at Albemarle
street by Prof. Dewar, and the occasion
viii be remembered by all who were pres
ent as the first at which liquid hydrogen
at once the highest and the coolest
liquid ever known TO exist-was seen out
side the laboratory, and in such substantial
quantities that vessels fun Of 1t were hand
ed round for inspection The Duke of
Northumberland presided. and the numer-
Gus audience included most of the new
honorary members. together with Lord
Kelvin, Lord Rayleigh, Sir George Stokes,
Sir Frederick BramweR, Sir Edward
FARMLAND, Sir William Croolzes, Sir J. W.
Barry, Sir James Crichton- Browne, Sir w.
II. Preece. Sir W. Roberts-Austen, Sir
Frederick Abel Sir Andrew Noble, Sir
Alexander c. Mackenzie Sir Henry Nance,
Dr. j. II. gladstone, Ny A; siemens, Dr.
tombstone Stoney and Dr. Ludwig Mond.
Prof Dewar said he did not intend to
take any long hight into the great work
Of the Royal Institution in the past, since
That had already been done by his coll
league. His object was rather 10 intro
duce his audience to a new instrument of
research-that was TO say, TO liquid hy-
vacuum tube immersed in liquid air, the
access of heat being by this precaudon
greatly impeded. They would notice it was
a transparent liquid in which there APP
peared a whtish deposit. This consisted of
solid air, and it was impossible to avoid
It's presence, because Immediately the cot
ton wool plug was removed from vessel
OF liquid hydrogen the air Of the atmos-
phere came under the influence of so low
temperature as to be at once frozen solid.
To prove that the liquid he was manip-
liquid hydrogen, Prof. Dewar put light
TO small quantity, a brilliant burst of
name being the prompt result. or its eX-
ceedIngly small density he gave an idea
by showing that a light material like
cork would not float on its surface, bat
sank to the bottom as IL 1t were lead. The
lowness of its temperature (about 440 be-
low zero, FahrenheiD he illustrated by
number of experiments. Thus solid
body immersed in il for short time was
shown 10 become so cold that the air
round it was lquefed and ran off In
drops, while when a lube containing liquid
air was plunged into it the air immedi-
ateiy became solid On this tube being
lifted out again a double effect was seen,
for the melting of the solid within II
yielded liquid air. which was also formed
by condensation on its outside surface.
An empty vessel placed for a short time
in the cold atmosphere just above liquid
hydrogen filed with solid air in the form
of snow soon melting into liquid. OXy-
gen in a sealed tube when lowered into il
quickly became solid. and when lifted out
il could be seen. as heat was absorbed, to
assume first the liquid and then the gas
eous form. A sponge of porous material,
soaked in liquid hydrogen and brought
into a magnetic field, apparently behaved
as if it was ma gnetic. That however,
was due TO the condensation of the oxy-
gen of the air, which, of course, was
magnetic, and though an observer might
in this way be easily deceived into think
ing hydrogen magnetic, Prof Dewar said
he was satisfied that it was nearly neutral
or diamagnetic.
Speaking of the real temperature of this
liquid. he said it was q degrees on the
absolute scale Chat is q degrees above alb
solute zero, which is placed al 273 below
zero centigrade or Gal below the zero of
Fahrenheit 1t had taken him nearly a
year TO come TO definite conclusion on
that point, because he could not get any
two thermometers TO agree. Pure plati-
NUNS resistance thermometers gave 30 de-
grees absolute Tor 23S degrees below zero
Centigfade), one of platinum-rhodium al
low q degrees, while hydrogen itself Is a
gas thermometer gave q degrees, a read
ing nearly identical with one Obtained with
a German silver electrical thermometer
The last part Of the lecture was devoted
10 the extraordinary low Vacua obtainable
by the use of liquid hydrogen. Thus bH
immersing one end of a closed tube in it
for short time and then sealing it off in
upper part which was substantially per-
feet, as was shown by the fact that the
electrical charge could not be made to
pass In conclusion Prof Dewar. after
exhibiting several other beautiful expert
ments, including one to illustrate the rap
idity with which gases We're discharged
into a vacuum. claimed that the liquefac-
ton of hydrogen was a triumph for the
DRY not less than for practice.
Lord Kelvin. in moving a vote of thanks
TO Prof Dewar for his brilliant, beautiful
and splendid interesting lecture, said
that If those present wished to measure the
Importance OF. the occasion, let them think
what Count Rumford. or Davy, or Fara-
day would have thought, could they have
been present. They could not have hop
ed for their scientific dreams and proph-
ecies to be so splendidly verified within the
century. The end of experiment in re-
search at low temperature had by no
means been reached, and, perhaps, in
few years substances YET unknown and
have been found which would bring the
experiment TO within degrees of the abb
solute zero.