Milford chronicle., 1893-04-14
MAKING LIQUID AIR.
a SCIENTIST EXPLAINS HIS CHEM
icAL DISCOVERIES.

Professor Dewar's Experiments May Prove
to BE the Greatest Investigations Of the
Century-PowerfuI Gases Reduced to .
FLUID siete.
The Pau Mall Budget Of London pub
lished 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 "his hq-
uefactions Of permanent gases and the
use Of wanna to preserve great cold mark
oneof the most important chemical dis
coveries Of the century, It is held BY
scientists that any gas may be hquehedl
If the pressure and cold may be obtained
and a vessel of sufficient strength to
Withstand the great pressures.
OF the gases that may be hquened car
bonic acid gas has been found 70 be the
cheapest and readiest made, and while It
has been known for many years that i
could bs liquifed it has generally been
so prepared only in small quantities for
scienti5c uses The use of compressed
airasa a motive power has presented many
difficulties. the principal one being its
bulkiness; hence large vessels must Dc
used in order to get sufficient amount
Of motive power, and it is hard to make
these strong enough and at the same time
light il weight
As motive power it Is used at a pres
sure Of from GOO to 800 pounds. But II
Professor Dewar has discovered an eco
nomical and ready way Of hquefying It.
It viii tend TO solve a problem IN carry
ing a motive power in storage bulk that
viii 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 j 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 21O degrees below zero, and the lowest
possible temperature is 274 degrees be-
low. If we could get some 30 degrees
lower down, we might liquefy hydrogen.
HYDROGEN has never been hquetied IN
free state yet.
Now, it's strange thing that air can
be made into a homogeneous fluid. Hon
would think, as oxygen can be liquehed
at -fs2 degrees and nitrogen not until
-192 degrees, that as you made the air
colder and colder the oxygen would be-
come liauid first and then the nitrogen.
saw that prediction made in stand
ard work only the other day. Now,
dare say. YOU viii ask why the oxygen
don't come down FIRST.
Stepping quickly back to the desk Pro
fessor Dewar took up pencil and began
TO draw with rapid strokes on the back
Of a letter. The diagram when it was
finished looked more like the law Of dl-
ninishing returns turned up on one side
than anything else that am acquainted
with. While he drew he rapidly ex-
plained how the influence Of atmospheric
pressure on 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
a little. drawing up the wrinkles between
his ewes. Now, that, in the old theo-
logical days, would have been taken as
a providential dispensation. The strange
thing is that when liquid air evaporatef
again they are under the same pressure
and the nitrogen goes of first, as you
would ss~ss-'t-.
bg,s 5alsssss.steln l12ud by acting on
M arS'z, 3 liquid R8ygen
sssma- -rtl:s ,,Tss.a darE -
,ck l-asr'k as indigo. Ozone
-~-,e 4nolecule as oxygen,
aI1N