The San Francisco call., 1897-05-09

purposes by mixing its escaping gases Win
atmospheric air in certain definite proper.
tions. Moreover, as a driving force III 1ne
way OF detonators, or explosive material 10
drive engines LIQUID air is obviously power
that can be under given conditions prontaoly
applied.
Hitherto the classic example OF metnoo TO
hquefv air and obtain oxygen was III
vented by Beatty and Cailletet In 1877. Win
their machine one began with caroonic aclo
gas. By means OF pump TINS gas was con, In
densed in q tube round which lay water at ~
degrees to keep the tube cool. The carbontc
acid gas, being reduced 10 very low tempera-
ture passed from The first tube into another
chamber with tube IN IL ana IN SO Colng IeIl
TO p lower temperature. Into this second tube
was pumped al hlgh pressure etnyIene gas,
which in turn fell 10 . low TEN perature, owing
10 the coIdness of the carbonic acid gas bath
ing the tube. The ethylene gas was then
passed from the second tube into third COM
partment and fell further IN temperature IN so
doing. The third compartment had likewise
q tube with an airpump attached. Into this
third tube was pumped oxygen gas and from
the ethyIene gas bathing II tho oxygen gas
reached a temperature OF 1872 degrees beloE
zero. Finally, the oXyg gen was let out into q
fourth compartment, in which was fourth
tube. The airpump attached to this fourth
tube having filled it with condensed atmos-
pheric air the latter was so reduced in temper
ature that when it in turn was re eaaed from
the tube its temperature was 273 degrees be-
low zero and IL appeared in the form OF drops
like water.
air, has q milky appearance from the pres
ence of some carbonic-acid gas, bubbles con-
stantly, and from its enormous cold emits a
>moka or cloud, like the top of very high
nis,-.,.a:I, and will only gradually resolve
l.scli again into air when exposed TO the ordl-
nary atmosphere.
Fluid air costs about 10 marks tsay 81 25)
Tor five cubic meters reduced. The new
method is the invention OF Professor Linde OF
Munich. 1t prod uces The liquid for 10 pfen-
nigs (say 21l cents for five cubic meters, and
II yields tne product either as gas or nun as
one wishes. This is one OF the most ingenious
pieces OF mechanism known. Its chlet lea
ture is its economy OF working, for 1t uses air
to refrigerete air. After the pump has worked
Tor a certain time one turns cock and the
liquid air runs out at temperature OF 213 de-
grees below zero.
In Professor Linde's method an airpump
OF five horsepower condenses air TO pressure
spiral tube and is let out in q cham Der, caus-
ing great cold; then II rises and passes on the
outside OF the spiral tube, ba thing IL and thus
cooling the new air that has been pumped into
the to be 10 take its place. This cooled air iol-
lows on into the ch amber, expands and
again lowers its atmosphere, then passes on
up around the same spiral be; but as its
temperature has become much lower the new
air in the tube is still further refrigerated.
This circulating process goes on un III the new
air pumped into the tube reaches the expan-
sion chamber at temperature OF 2T3 degrees
below zero, when IL drops into the chamber in
the form OF liquid. Thus the air, steadily
cooled, Is made TO reirlgerate the newly
pumped air more and more until the nece ssary
degree of cold is attained.
Another idea, which may or may not be an
Improvement is to have the pump and all
parts of the machine kept very low in tenn
perature.
Air, in the cheap, portable form of liquid
rich in oxygen, can be used for many purposes
in manufactures and the trades. The discov
cry of q cheap method may be Of importance
TO American manufacturers
Mr.. Rex of San Francisco. who delivered
the lecture at Stanford University last
Monday night, is fully advised of the
great progress made by the German
scientists but does not hesitate to assert
that still greater progress has been made
in New York. Within few weeks, pos
sibly some time this month, a definite
statement, expressed in scientific terms,
may convey to the public all the import
ant facts relating to the new discovery.