The times., 1899-10-29
FACTS ABOUT LIQUID AIR
An Inventor DispOses of Some Mis-
taken Theories.
DIR. stephen II. Emmons Offers n Pom
ular Explanation OF the New Power
Derived From Constituents of the
AtmOsphere-Its Production Like
Iy to become Great Industry,

" AN4AAAA ZIG past ear since the DOSSl-
buities of liquid air have come to be
topic Of general interest, much has been
written concerning its so-called miraculous
powers. few months ago it was be-
lieyed that in the new agent perpetual mo-
tion had been discovered, which would en-
power production. While 1t is generally
admitted by scientific men who have made
a careful study of the new fluid, that its
application will eventually displace steam
and electricity to large extent it is not
believed that the revolution will be as
great as was first anticipated. It is, how
ever, admitted that liquid air is destined
to play in the immediate future as conspic-
uous a part commercially as steam and
electricity do in the present day.
There is no question in the minds of
men who have carefully studied the prop
critics Of the powerful liquid that il can
be produced in quantities at a sufficiently
low cost to make its application eminently
practicable Machinery for producing it has
been perfected and tests of its efficiency
have been made which plainly indicate the
opening of a new industry.
IT'S Use Abroad
In France and England liquid air is al
ready employed commercially to advan-
tage, and its use is growing rapidly In
the eastern cities of the United States,
notably in New York, Philadelphia, and
Boston, companies have been formed and
capital in large amounts invested for pro-
noting the commercial use OF liquid air
he
in the past few months, and preparations
have not yet been completed for placing
the liquid on the market for general use,
but there is every Indication that at no
distant time a new industry will be de-
veloped which will rival in magnitude the
telegraph, telephone, and electric light in
terests of the country.
Dr. Stephen II. Emmens, of New York
who IS probably the leading authority on
liquid air in the United States, and who
is the inventor Of an apparatus for pro-
ducing the fluid, in an interview with a
Times reporter, gave an interesting and
instructive talk upon liquid air and its
probable value as a commercial agent. He
said:
Very few attempts have yet been made
to give the public very accurate informa-
ton as to Iiquefied air and It's probable
utilization as an industrial agent. Some
well-illustrated articles in popular maga-
zines have been published, and some enter
taining lectures have been delivered; but
the general tone OF the statements thus
disseminated has been one of sensational
ism, based, for the most part, upon that
little knowledge which Pope long ago
pointed out was a dangerous thing Or
the other hand, the strictly technical jour
nails and sundry learned professors have in
dulged in criticisms and denunciations
every whit as one-sided and in many cases
as incorrect as the very exaggerations and
errors which they sought to overthrow.
The truth, as usual lies between the
extremes. Liquid air is not the miracle it
has been alleged to be by the peripatetIc
lecturers, the magazine scribes and the
hamboyant advertisers. Nor is it a mere
scientific toy, and an impracticable natural
vehicle OF power, as maintained by engi-
neering editors and so-called leaders of sci
ence. 1t represents an important step for
ward in the march of industrial progress,
and it as surely destined to minister TO
our material wants and add to the fortunes
Of mankind as was the case with steam
electricity, or any other great advance in
the art Of controlling natural forces.
An Experts Explanation.
"In order to understand what liquid air
AGG44S -, We AhOSL bG5lA by 4tLHGulBcIlLl7
what we know as to the condition of mat
ter in general. The metal, lead for ex-
ample, is a heavy solid body. But If we
heat it to a temperature Of a little above
two degrees, Fahrenheit, it becomes Ii
quid and, if We urge the heat to a higher
point, the liquid becomes converted into
an invisible gas. The same thing is true
of gold, silver, iron, copper, and all other
solid metals, which, without any excep-
tion can be liqueied and gasified by heat
ing to various temperatures. 1t is also
true of mercury, a substance that is pecu-
liar to us in its liquid form. If We heat
IT, we obtain a gas; il we cool it we OBJ
tain a solid. Water and oil display SINH
lar changes; they can be frozen by cold
and YapOrized by heat. CarboniC acid
forms part of the atmosphere that sur
rounds US and is generally in the form Of
an invisible gas. But if we require it in
the form OF a liquid we can buy it as such
in the market; and we can also obtain it
as solid mass; the change of state from
gas to liquid and from liquid to sold be-
ing a mere matter of cooling. 1t is there
fore quite in accordance with our general
experience that air also should be capable
of existing as q gas or as a liquid, or as
a solid, according to its degree of heat or
cold.
Changes in Matter.
There is something else that we know
by common experience with regard to the
changes of state experienced by matter.
We see that gases are bodies that are self
expansive and that therefore exert more or
less pressure upon the sides of the vessels
in which they are confined. And we find
their pressure to increase with their tenn
perature. Steam, for example, at 2l2 de-
grees Fahrenheit has the same pressure
as the surrounding atmosphere, viz, be-
tween fourteen and fifteen pounds per
square inch. But If it's temperature be
raised to 800 degrees Fahrenheit. its press
ure becomes siXty-seven pounds per square
inch, and at 400 degrees Fahrenheit. it ex-
erts a pressure of about $50 pounds per
square inch
These phenomena afford a key to the
whole problem of liquefying gaseous bodies.
If we can contriye TO keep up a pressure
of 400 pounds per square inch, we need
only cool the steam down to a temperature
a little below 400 degrees, Fahrenheit in
order to convert it into water. If the
pressure be but siXty-seven pounds we
must cool the steam down to below 300
degrees Fahrenheit if We wish to lquefy
it. And if the operation be conducted in
an open vessel under ordinary atmospheric
pressure we must so down to a little be-
low 2l2 degrees Fahrenheit Similar fea-
lures characterize all other gases. The
degrees of cold and pressure vary accord
ing to the particular gas operated upon
and the greater the pressure we employ
the higher viii be the temperature at
1la ,f inc n