Evening star., 1896-08-22
Compressed Aira.asHas Entered the
Field IA Stay.
IN EVERY DEPARTMENT. OF EFFORT
Transportation PrpbIems That May
Now Be,6o|ved.
DIFFICULTIES OVERCOME

Copyright, 1896. by the s. g. Mcclure CO..
It Is only with its recent very successful
application to the purposes of street trac-
tton that the general public has awakened
to the immense utility and the wide possi-
bi!ities Of compressed air. Within a few
years, very largely within the last decade.
1t has come to undertake such a multi
plicity of tasks that mere enumeration of
them Is astonishing. We have long known
ef the value of air for stopping cars in
the shape Of the Westinghouse brake; now
1t Is used to start cars as we'll We are
fairly familiar with its work in drilling out
rock excavations for the modern sky
scraper; it is another matter to learn
that this same compressed air drill, used
in the mine, has enormously added to our
wealth of gold and silver, OF coal and iron.
and copper, through the cheapening of
the production 1t has caused It is still a
further matter of surprise that this pro-
team force has turned canal digger and
was the largest single agent in the con-
structton OF Chicago's great drainage
canal, in many respects the most wonder
full canal In the world.
We are again acquainted with the pneu-
matte dynamite gun. where compressed air
| is employed to throw huge charge Of high
explosive to the distance Of a mile or so:
| 1t Is another matter to think Of this same
force cleaning carpets and dustlng cushions.
1t has been successfully employed to pro-
pei locomotives in mines; 1t Is equally use
| ful to shear sheep. 1t will operate q block
| signal or 1t will steer a ship It was a
| novel thing when we read Of the buildings
Of the worlds fair being painted by COM
pressed air, but 1t is common enough
thing now; 1t is even used to polish and
sandpaper cars as well. In Paris 1T is em-
ployed to run clocks and as a cooling agent
In refrteeratorS; 1t runs motors propels
sewing machines, lifts scenery in the thea
ters, drives lathes and printing presses and
street cars, and is the motive power in all
the little shops which turn out the curious
articles de Paris, which are 80 great a
source Of revenue to the French capital.
Other Uses.
We know Of its use in carrying mails in
pneumatic tubes. It Is now proposed to
make 1t carry freight. 1t is employed to
raise sunken vessels. and very shortly it
will be introduced on the Erie canal to
operate the locks By the Dutton pneu-
matte high-lift lock It is proposed to pick
up great ocean liner end lift 1t as high
as Niagara with "less effort and In less
time than is now required to elevate q
clumsy barge the height Of a bean pole
In the railroad shops it is everywhere.
running machinery. koisting huge loads,
riveting bolts. driving hammers, is en-
ployed in forging and in every conceiv-
able variety of work. In Kansas City
beeves are slaughtered and the meat
dressed all by compressed air. 1t is an
excellent pump. especially for deep wells;
it is used to pipe oil and pump chemicals.
1t is used by the physician and the sur
geon in many delicate operations. 1t
makes good elevator hoist for grain.
With compress ed air you may dump
q dirf with
pressure of your thumb. 1t Is used in
sculpture and In stone Carrying. 1t makes
a good dredge. it raises and lowers rail-
road gates. 1t will copy your letters, run
summer fans. 1t Is used in the sugar re-
f1nery and in the making of asphalt and
Of rubber. and still again in the delicate
manufacture OF fine silk. In fact, there
seems hardly limit to the uses to which
1t may be put.
The wonder Of 1t now seems that all this
has not been done long ago. Compressed
air Is OF new. in the sense that electricity
Is new: How, then, does 1t come that it is
only Of very recent years that 1t has been
generally used? Probably the chief rea-
son will appear with hardly any explana-
t1on at all. 1t was largely a mania for
things electrical. 1t seems absurd TO say
that the business world has been carried
away with mere enthusiasm. and yet
this Is literally the case. The beginnings
OF the use Of compressed air were almost
coincident with the introduction Of cleo
trEity. ana compressed air be1ng known,
its possibilities being capable Of more or
less accurate definition. 1t was literally
neglected for its less known, more snowy
and mysterious rival
Electricity Now Well Known.
It is a frequent matter of remark now
that had 1.-THE of the money and brains
and genius been expended In the develop
ment Of compressed air as has been given
to electricity, the present relation Of the
two forces would be reversed. For a long
time electricity represented the unknown;
It's possibilities were unquestionably great:
FOR time they appeared boundless. Now,
however, its capabilities are more clearly
outlir ed, its powers definitely known, and
mechanical and inventive genius Is turn
ing to the development of the force Of air.
The three chief factors Of recent prog
ress are perhaps the perfection Of the
COMPRISING apparatus and Of the reheat-
ing process and Of the ron-bursting steel
reservoir. When compressed air was first
tried 1t was found that the loss Of power
IN the process was enormous Then. again.
there were thermodynamic difficulties with
out number. II you put thousand cubic
feet OF air into the space Of single one,
you develop high degree Of heat. and in
order to use the air this heat must in some
way be drawn off. Similarly, air at high
pressure when released cools rapidly; the
result Is freezing and clogging. 1t used to
be thought that these difficulties were for
practical purposes insuperable.
Now, however, these very difficulties. Or
rather, the causes which produce them,
are turned to prolific such excellent profit
as to AFFORD an apparent paradox. 1t seems
idle to assert that you are able to get out
or machine as much power as you put
into it-that this is perpetual motion. And
yet this Is almost literally true in the pres
ent day use of compressed air.
IN this country there are air compressors
built so perfectly that the loss of mechan-
ical efficiency in compression is only about
per cent. and of the total efficiency only
10 or ~ per cent: that Is to say. II you use
up hundred horse power in the compress
sion OF the air you. will have force that
Will, In the case of the best type of air
compressors. give you: eighty or ninety
morse power in return, Here incidentally
Is another triumph OF American mechan-
ical genius. In the famous Popp system in
Paris, where COMPRESSED air is distributed
through 125 miles of mains. the efficiency
reallzed is less than 80 per cent, little
more than half that in this country.
Wonderful Mechanism.
The compressor ,Rhich does this work is
a beautiful machine Of, what is known as
the four-stage type That is to say. the
air Is first driven up to about eighty
pounds pressure and then cooled by a water
jacket. then turned into second cylinder.
where 1t is compressed still further, then
cooled again. and so on up to the desired
hnc I>air Liant q fhn