The Sun.
London, England, 1867-07-12 00:00:00

COLONIAL.

TEA —Thero has been a very moderato inquiry ; the
trade deferring. their operations until the public sales of
China produce, which commence on Tuesday next.

SUGAR.—The market continues very dull, and late rates
are with difficulty maintained for West India. In the
refined market quotations are also a shade lower.
COFFEE.—A fair demand has prevailed for Plantation
Ceylon, and full rates are generally current, while coarse
and info; for descriptions are neglected.
Rim—For soft grain descriptions there is a good de-
mand, but without any change in values.
INDIGO.—The public sales have continued to progress
with considerable spirit, and extreme rates have boon ob-
tained for superior qualities.

TALLow.—Business has remained very quiet, and quo-
tations remain unaltered, P.Y.C. on the spot being 44s 9d,
and last three months 45s 3d to 45s 6d.

PETROLEUM AS FUEL.

Ina late number we gave an account of the application
of petroleum as a means of generating steam for propel-
ling vessels, for which purcose the United States steamship
Palos was fitted with the necessary apparatus. We now
give the account of the trial trip, taken from the Boston
Advertiser of the 15th June:—

The Palos left her dock at the navy yard at ten minutes
before 11 o'clock, and returned to it shortly before one.
When she had been out fifteen minutes it was found that
she was moving through the water at a rate of over eleven
and a half miles an hour, and she was gaining steadily
with thirty-eight pounds of steam, having started with
thirty-five pounds. This fact caused considerable sur-
prise on board when it was shown that, under the coal
as fuel system, upon its first trial trip, when the vessel
was now, its best time was only eight knots an hour, and
that it had not made bettor time than eight and a half since
until now. It was further clearly demonstrated to tho
intensely interested passengers that the Palos was in very
poor him, that her bow stood up from the water and her
stern was planted down ; that she dragged dead water and
in several other respects was not all right, and therefore
that the rate of speed under the circumstances was rather
extraordinary.

The vessel went down the harbour past the forts and
islands, and out to sea a short distance beyond Boston
Light, and then returned by a somewhat circuitous route.
The first 48 minutes she made over eleven and a half
miles, and ran upon the entire trip twenty-five miles in
1 hour and 55 minutes. With her action and the success
of tho experiment there was general satisfaction among
the passengers, and much enthusiasm was shown by the
scientific gentlemen.
The Palos, which made this novel trip, is a sm ill gun-
boat, and formerly used four coal fires, and had a crew of
twenty firemen and coal passers. With the petroleum
apparatus she requires a crew of only three men,
as the supply of fuel is easily regulatee, and cin-
ders or ashes are made. The petroleum is supplied from
two-large iron tanks placed on deck, each taut: having a
glass gauge at its side to indicate the height of the petro-
leum, and a vent pipe upon the top to permit the escape of
vapour. From these tanks the petroleum is conddctod by
half-inch pipes to the boiler furnace., It there drops into
iron retorts,. heated by boilers placed beneath them, and is
instiintly vapourised. This vapour, in burning, is mixed
with steam, decomposed by passing through the pipes
paitially filled with iroia filings, and with oxygen sup-
plied by atmospheric air, forced in by a common air
pump. The heat thus generated is intense, and it is a
noticeable fact the combustion is so perfect that no smoke
is 'perceptible.. A diminution of the supply of air or steam
at once creates a smoke. Her engine is about 850-horse ,
power.
This initial voyage will be followed by several others ,
so as to completely test the invention. Should it bo
found to be all that promises, undoubtedly it will
create, a revolution in the manner of propelling
steamers and locomotives, and such machines. The
advantages of petroleum as fuel over coal are
i_appa-
rent. For the trip yesterday about four barrels of oil
were used ; the captain of the boat declares that sozo
thie
or eight tons of coal would have been consumed
in
same work. A large amount of coal would have b_ eenn
required to start the fires, and muck would have
bee
wasted when the sail was completed, as the he.at w.as
kept well up until the last moment. Wa hen
needed ono
given out yesterday that the fireso or three throttle
were
longer, by simply turning.
t
valves the times were extingutshed, and in a few minute's
time the fires wore down. Of course there were no ashes
and no dirt, and tho fire-room was as clean as could be, and
the neat carpet with which the floor was covered was not
soiled in the least.
Colonel Henry B. Foote, of Tennessee, the inventor,
superintended the work in the fire-room, which was ex-
ceedingly light and not disagreeable, and Engineers C.
W. Pennington and Henry W. Scott had charge of the
engine.

The good results of the Compulsory Vaccination
Act are strikingly exhibited in the return of deaths regis-
tered iu the Dublin district during the past quarter. The
estimated population is 314,409, and the total Number of
deaths registered during the quarter WOO 2,173, yet not one
of the) wag from omalJpox,