The Princeton union. [volume] (Princeton, Minn.) 1876-1976, 1893-06-08
MAKING j LIQUID AIR.
a SCIENTIST EXPLAINS HIS CHEM
CAL DISCOVERIES.

a SClEN llSl EXPLAINS HIS CHEM
CAL DISCOVERIES.
Professor Dewar's Experiments May Prove
to BE the Greatest Investigations of the
Centnry--Powerful Gases Reduced to q
Fluid State.
The Pail Mall Budget of London pub
ished an interview with Professor James
Dewar on what is represented as being
"a great scientific discovery" that Of
making liquid air. Introductory to the
interview the article says that This liq-
nefactions Of permanent gases and the
use Of wanna to preserve great cold mark
,ne of the most important chemical dis
coveries of the century" It is held by
scientists that any gas may be iquefed
If the pressure and cold may be obtained
and vessel of sufficient strength to
withstand the great pressufes.
OF the gases that may be iquefed car
bonic acid gas has been found to be the
cheapest and readiest made, and while it
has been known for many years that it
could be liquifed it has generally been
SO prepared only in small quantities for
scientific uses The use of compressed
air as a motive power has presented many
difficulties, the principal one being it's
bulkiness: hence large vessels must be
used in order to get a sufficient amount
of motive power. and it is hard to make
these strong enough and at the same time
light in weight.
As motive power it is used at a pres
sure Of from 600 to 900 pounds But if
Professor Dewar has discovered an eco
nomical and ready way of iquefying it,
it will tend to solve a problem in carry
ing a motive power in storage bulk that
will be of great benefit to the students in
this line In the talk with the represent
alive of The Pail Mall Budget, he says:
well. don't think there's very much
to say, because I've told all have to tell
about the matter in my two lectures,
but do believe there's a great deal more
to be learned about the subject. You
see, at present we've got these gases down
to 80 degrees below zero, and the lowest
possible temperature is 274 degrees be-
low If we could get some 80 degrees
lower down, we might iquefy hydrogen.
Hydrogen has never been liquefed in a
free state yet.
Nov, it's strange thing that air can
be made into homogeneous fluid You
would think. as oxygen can be liquefed
at -1s2 degrees and nitrogen not until
--l92 degrees. that as you made the air
colder and colder the oxygen would be-
come liquid first and then the nitrogen.
/ saw that prediction made in stand
ard work only the other day. Now, l
dare say. you will ask why the oxygen
don't come down first"
Stepping quickly back to the desk Pro-
tessor Dewar took up pencil and began
to draw with rapid strokes on the back
Of letter. The diagram when it was
finished looked more like the law of di-
minishing returns turned up on one side
than anything else thatl am acquainted
with. While he drew The rapidly ex-
planned how the inhuenoeof atmospheric
pressure OH the different volumes of nj
trogen and oxygen in air makes them
boil almost exactly at the same tempera-
ture. As he made each point he frowned
little, drawing mp the wrinkles between
mis- eyes. Nov, that. in the old theo-
logical days, would have been taken as
Il providential dispensation. The strange
thing is that when liquid air evaporaues
again they are under the same pressure,
and the nitrogen goes off first as you
would expect.
Ozone can be liqueied by acting'on
the vapor given off from liquid oxygen
by electricity. It is splendid dark blue
L 'lor, almost as dark as indigo. Ozone
.las not the same molecule as oxygen,
md the electricity breaks up three twos
INTO two threes That is the secret of it,
The queer thing about liquid ozone is
that when it goes back into gas again it
explodes. You wouldn't think it, but it
IS stronger than dynamite as an explo-
sive. It's simply because the ozone goes
back into the molecular form of oxygen
so fast. The force that comes from the
electricity makes it explode without
meeting with any outside body. It's
tremendous explosive.
I'VE have discovered that liquid oxy-
gen acts as lens It is so transparent
to heat so to speak, that even at 1872
degrees below zero you can focus heat
on it from one side and light piece of
paper by it on the other You know
that's just what happens il the earth
The suns heat gets focused on to the
earth through the lens formed by the
vacuum Of space, which is so cold that it
hasn't any temperature at all-absolute-
ly Zero" .. ....-
Professor Dewar gave lecture on
Liquid Air" at the Royal institution i.
the presence of the Prince Of Wales, tho
Duke Of York, Lord Salisbury and other
notable persons. He showed that by the
withdrawal Of heat the air is converted
into liquid with total loss of chemical
properties, incapable Of supporting COM
bustion, or of entering into combination
even with phosphorus and sodium, while
certain physical properties remain. The
conversion Of oxygen into ozone was also
described, and the retention by oxygen
of its peculiar optical properties at the
lowest temperature was demonstrated
by the very dense and we'll defined bands
of its spectrum In ordinary conditions