The Portland daily press., 1871-05-26
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| A few months ago the PRESS descriDed some
experiments then being made in this city by
Mr.. Robert Spear, with compresstd air as
| motive power, and to demonstrate the practl-
| cability of transmitting mechanical power any
| distance from its source without parting with
| any portion of its force. These experiments
have been pushed to a successful termination,
and we may, we think, say that MIR. Spears
| discovery will make a complete revolution in
manufacturing enterprises by diminishing the
cost of production, and give every. mechanic
an agent in his own works hop that is inexpen-
sive, economical, and almost as readily usedas
gas OF Sebaeo water. Mr.. Spear and oEe OF
his associates gave an exhibition OF the new
discovery yesterday loren ION TO party OF SCI
entifo gentlemen and merchants at Hoiyoke's
wharf, where they have fitted up experimental
works; and with one accord the testimony OF
the witnesses is that The new motive power is
destined to effect comp Iete revolution in me.
cbanic arts, and is parallel with the electric
telegraph as a beneiactor to society And yet,
the whole system of applications when once
seen, is very simple. Common air is compress
ed by steam or water power in reservoir, 10
any desired pressure, and from thence distrb-
uted in pipes to any point, however distant,
where its use is desired OF course the pipes
are practically part Of the reservoir, and the
pressure on them is the same, and to prove
that no power is lost, a guage placed at the ex-
treme point of the pipe indicates the same
pressure'as one at the reservoir. A common
valve lets the compressed air upon small and
insignificant looking engine, consisting OF only
a stvalv a. hos - Mat ho1o,
wheel. large Daniels planer, situated 4SO
feet from the reservoir, was first shown, and
hackmetac ship-knee put nnder the knives
The work was handsomely done. The air was
then turned into aportable steam engine in
the building and it was readily driven up to
its full capacity ofs12 horse power. Other ma
chimes were afterwards. driven by the same
means, and the efficacy of the power fully
demonstrated. Mr.. Spear hasalso invented a
governor, which is operated by pressure instead
of motion, like the governor of steam-engine
It's operation is shown by the following illus
tration suppose the pressure at the reservoir
is 100 pounds to the square inch, and.a mechan.
ic mile away requires but % pounds to drive
his works. He graduates his governor, which
is attached 10 his engine, at that rate, and no
matter what the fluctuations at the reservoir
are, SO long as they do not 60 below his initial
point, he receives steady and uniform now
or. 1t is very ingenious piece of mechanism,
but it would require too much space to describe
its construction.
Mr.. Spear claims for his discovery the great
est economy aud safety. By the use OF 80
horse power engine air can be compressed in
reservoir to an extent equal TO a 100 horse-p pow
er engine. The pipes can be extended to al
most an indefinite extent, and the friction in
turning curves in the pipes is overcome BY a
very simple invention in respect to their con-
struct ON. BY the use of this power, the ex-
pense of providing and maintaining long lines
of shafting in large shops is overcome, and the
necessity of keeping large boiler and engine
running where but small portion of the ma
chinery in the shop is in use-as is the case al
most daily in nearly every establishment-is
removed. Every piece of machnery-from the
largest iron planer or lathe to sewing ma
chine-can have its independent engine =
When one of these is required, the workman
opens his valve, starts his engine, drives his
lathe, and when his job is done the engine is
stopped, and the power is saved which under
all our present methods is wasted. Mr.. Spear
calculates that the tidal force at Tukey's
Bridge is sufficient to furnish compressed air.
power for all the machinery now run in the
city of Portland. Our narrative may seem
strange, almost incredible, but we only relate,
very briefly, what we have seen, and we have
no doubt that Mr. Spear, who loves TO explain
his discovery, will abundanty satisfy any one
who will call on him. Some Of our most ac-
complished engineers are enthusiastic in its
praise, and alter months of the most careful
observation the gentlemen at the Patent Of
flee in Washington have PRONOUNCED it a most
wonderful and valuable work. aS ~