The Liverpool Standard and General Commercial Advertiser.
Liverpool, Merseyside, England, 1841-10-22 00:00:00

IMPORTANT INVENTION IN MACHINERY

Our attention has been called, by an article in one of the
provincial newspapers, to a very important mechanical in-
vention, for which a patent has recently been granted to two
Scotch gentlemen, and which promises to effect a greater
and more beneficial change in the working of machinery than
has taken place since those most brilliant discoveries of Watt.
The two great drawbacks of the steam-engine (besides the
large space it occupies) have been the bulk, and the conse-
quent expense of the fuel which it requires—the latter pre-
venting its application to many purposes for which it would
otherwise have been a most effective agent; and the former
impeding its locomotive energy, and confining it, particularly
as regards navigation, within comparatively narrow lim ts.
Any reduction in either of these respects is thereby obviouisly
so much clear gain. The invention to which we allude pro-
mises to effect a prodigious saving in both, by diminishing
the expenditure of fuel to somewhat less than one-fifth of
what is now required for an equal degree of power. It has
already, we are informed, been put to the test by the con-
struction of an engine of about 20-horse power, which has
far some time been driving all the machinery of an extensive
foundry with no larger consumption than we have just men-
tioned, and with every prospect of a considerably greater
reduction being effected by some slight changes in the details.
The motive power used is the common atmospheric air; and
another great advantage of the new engine arises from a
saving of space, equal to what is usually occupied by the fur-
nace and boilers of a steam-engine. If these things be so,
it is impossible to calculate the results to which so important
a discovery must lead. The following is a description of the
engine referred to :

The air-engine now working at the Dundee Foundry, for
which a patent was lately taken out, is the joint invention of
the Rev. Dr. Stirling, of Galston, and of his brother, Mr.
Stirling, engineer, of Dundee. The principle of the inven-
tion consists in alternately heating and cooling two bodies of
air confined in two separate vessels, which are so arranged,
that by the strokes of two plungers, worked by the engine,
the whole of the air contained in one of the vessels is sent to
the lower end immediately over the furnace, and is conse-
quently made quite hot, while the whole of the air contained
in the other vessel is at the same time transmitted to the
upper end, which is cut off from any communication with the
furnace, and is therefore comparatively cold. The expansion
caused by the heat renders the air in the one vessel alter-
nately much more elastic than that in the other ; and the
two ends of the working cylinder, which is fitted with a piston
similar to that of a steam-engine, being respectively con-
nected with the two air vessels, a preponderating pressure is
produced, by turns, on each side of the piston, which is
thereby pushed to the opposite end of the cylinder, and so,
by the alternate action of the plungers in the two air vessels,
it continues a reciprocating motion, and is applied to turn a
crank in the same way that a steam-engine does. It has
been satisfactorily shown that this engine may be worked
with very great economy of fuel as compared with a steam-
engine. The principal means of producing the saving
is this—that of the heat which is communicated to
the air from the furnaces, only a very small portion is
entirely thrown away when it comes again to he cooled ;
for. by making the air, in its way from the hot to the cold
end of the air-vessel, to pass through a chamber divided into
a number of small apertures or passages, the great extent of
surface with which it is thereby brought in contact, extracts
from it in the first place, but only temporarily, the greater
part of the heat, and afterwards restores it to the air on its
passage back again from the cold to the hot end of the vessel.
The process of cooling is finally completed, by making the
air pass through between a number of tubes in which there is
a current of cold water, and thus far the heat cannot he made
available again ; but the portion which is abstracted in this
way is very small. As a sufficient expansive power could
not be attained in so small a space without greater alterna-
tions of temperature from using air of the common density of
the atmosphere, the air used is pretty highly compressed,
and a much greater power is thereby obtained upon a given
area of the piston. A small air-pump, worked by the engine,
is therefore necessary to keep up the air to the requisite den-
sity ; but very little power is expended on this ; all that is re-
quired of the pump, after the engine has been once charged, be-
' ing to supply anyloss of air that may arise from leakage, which
is found to be very trifling. The machine has been working oc-
casionally for above six months, and it has been proved to be
capable of performingadvantageously the amount of work which
the inventors had anticipated from their calculations and pre-
vious experiments. It has now for upwards of a month been
driving all the machinery at the extensive engineering works
of the Dundee Foundry, which a steam-engine of approved
construction had hitherto been employed to do ; and it has
been ascertained that the expenditure of fuel is, ceteris pa-
ribus, less than one-fifth part of what was required for the
steam-engine; but as considerable improvements are con-
templated in some of the details, it is confidently expected
that a much greater saving will eventually be effected. The
whole machine, including its furnaces and heating apparatus,
stands in about the same space that a steam-engine of equal
power would occupy without its furnaces and boiler. Taking
into account the saying of space along with the vast economy
of fuel, this inception must necessarily be of immense impor-
tance for all ordinary purposes requiring motive power. As
an instance, it !could reduce the expense of the power em-
ployed in driving machinery in Dundee alone by at least
I:23,000 or -£30,000 a-year. But, viewed in reference to the
purposes of navigation, it must lead to results more extraor-
dinary, and will render a voyage to India round the Cape, by
machinery, a matter of perfectly easy accomplishment.—
Mining Journal.

THE TEA TRADE--LONDON, MONDAY.—The market for
tea has been steadier since this day week, and the public
sales have gone off much better than could have been antici-
pated, seeing the heavy supplies that have come in continually,
and the still larger quantities daily expected. Great difference
of opinioia exists, swayed, no doubt, by interest in many
cases, as to the future range of prices ; but as some of the
dealers unconnected with speculation have suffered their
stocks to get very low, as a matter of prudence in the event
of any sudden change in the state of affairs at Canton, they
are ohliged to come into the market as purchasers for present
wants, and this prevents a fall in priees. The deliveries last
week amounted to 463,550 lbs., being an increase on the
previous fortnight.

DON MONF.V MARKET AND TRADE
REPORT.

WEDNEi4DAY EVENING.—The tenour of the intelligence
from the Uhired States was regarded in the City and on the
- Stock Exchange as of rather a favourable complexion, but
why does not so clearly appear, unless it must be taken for
granted that people having made up their minds to find
M`Leod tried, condemned and hung by the present arrivals,
were agreeably disappointed that no one of these grave events
had taken place so late as the 2d instant. Upon the strength
of this more encouraging aspect of affairs Consols improved
sto 87-1 to 8 for money, and 884- to for account. Bank Stock
was 162-i to 31.. India Stock 2422- to 34. Exchequer Bills
10s. to 12s. premium.
In Foreign Stocks as in the Home there was not much
bu-
siness doing. Dutch Two-and-a-Half per Cents were 51-4. to
' the Five per Cents. 991 to Belgian 102 to 3. Spanish
improved to-day, the Active with the Coupons being 20k to
I. Portuguese Five per Cents 294- to the Three per Cents
171 to 18. Brazilian 42 to 51. Mexican 23-i to 41,. Co-
lombian 18i to 191.
The markets for colonial produce were firm, with a
moderate business doing. _

The public sales of tea were brought to a close to-day.
The result is a decline of Id. per lb. on green teas, and about
former prices for other sorts. Company's Congou was at
Is. 91d. to Is. 9&d. per lb: cash.
Tallow was steady to-day. Prime yellow candle, 475. 6d.
per cwt. on the spot.
In the Hamburgh commercial markets during the week
ending the 15th instant, coffee was quiet, owing to the arrival
of supplies. Sales 5600 bags Brazil, at 31d. to 5d., and 1100
Domingo, at 4kd. to Cid. sell. The ord and good ord sorts
were lower. In raw sugar large transactions; 800 to 9uo
boxes white and brown Bahia; 1300 brown and yellow
Havana; 6000 bags 'Manilla; 400,000 lbs. molasses. Rice
sold for present wants. About 1000 boxes Cassir Lignea sold.
English pimento was at 3 1-16 to 34. sch. English pepper,
no alteration. Auctions of tobacco were coming on.