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ARTICLE X.
OF THE VOLCANIC STEAM ENGINE.
IN our pursuit of means to prevent the loss of the heat
which is carried up the chimney of the furnance, let us have recourse to
the works of nature: view the natural volcanoes, where the fire burns without
the aid of atmospheric air; where all the elastic fluid generated by the
fire dissolving the fuel, (see article 4) and all the steam formed by the
water that may occasionally come in contact with the fire, united, forms
the most terrible and powerful of all steam engines; in which the furnace,
boiler, and working cylinder are united in one, working on the simple principle
of applying great elastic power; casting up mountains, and making the earth
quake as she brings her strokes. To apply these principles as far as we
can, we make a cylindric boiler, about 36 inches diameter, 8 or 10 feet
high, with a furnace inside of it 18 or 19 inches diameter. Both the boiler
and furnace are united to the same heads, the fire being inside of the ivater,
and the smoke-flue turned downwards through the water to the bottom, where
the smoke is vented and rises in many streams of small bubbles, that it
may impart all its heat to the water to generate steam. The elastic fluid
generated by the combustion of the fuel, which we may suppose is 2000 times
the bulk of the fuel, and the air used to kindle the fire, expanded by the
heat to double its original bulk, unites with the increased quantity of
steam, to work the engine with great
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elastic power. But until we can discover a fuel that will burn without the aid of atmospheric air, or until we can find means for kindling the fire with a blast of highly rarefied steam, as may be the case in volcanoes, we use a forcing air pump to force in air to kindle the fire. This form of engine will work with much less fuel, and be much lighter than any other. It would therefore be more suitable for boats or land carriages, &c. I made a small boiler on this principle, which operated favourably; but being weary of the trouble and expense of putting new principles into practice, I declined the pursuit until better prospects open, or a more favourable opportunity offers. *
When this principle is put in operation, in addition to
those already explained, I conclude that all the principles of nature suited
to aid us in working steam engines, are taken in, excepting one which would
enable us to work a steam engine without fuel; which I conceive is only
to be done by collecting the rays of the sun to boil our water, to generate
steam, which may be done by plain mirrors and perhaps with much less expense,
than may at present be supposed.** It remains for us to
*The fire will burn more freely in this furnace, in proportion as the air is compressed round the fuel, for the same reason that a candle burns brighter in the receiver of an air pump when the air is condensed, and dimmer as it is exhausted.
**Many may think this idea chimerical, until they consider that water
exposed to the single perpendicular rays of the sun, in a suitable vessel,
will soon acquire the heat of human blood, 92 degrees, notwithstanding the
constant evaporation going on, which carries off the heat as fast as generated.
Experiments may determine how many single rays must be collected to triple
the heat, from 92 to 276 degrees in the water, which, by the table, (art.
3)
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improve in the application of those principles until we
discover others, if there be any.
would produce steam of elastic power 60 pounds to the inch. This would work a very powerful engine, to raise water in hot countries for various purposes. The rays collected to a focus by a convex lens, 36 inches diameter, produced a far greater degree of heat than any furnace ever had. How many lens can we suppose would he necessary to boil water to work an engine? But we need not go to the expense of lens; 100 plain mirrors containing each 9 superficial feet, and which might he constructed of 9 small glasses of one foot each, fixed in a frame, may collect rays sufficient for a powerfiul engine. How did Archimedes burn the fleet which invaded Syracuse?
I am fully of opinion that the time will come when water will he raised in great quantities by the heat of the sun at a very small expense, for various purposes; but the expense of such inventions cannot, in many instances, he borne by those who have the mental powers to design them; at least it is highly imprudent for them to risk it. In such cases aid from government becomes necessary.