The Sun.
London, England, 1848-07-01 00:00:00

NAVAL INTELLIGENCE.

The Dragon, 6, steam-frigato, Captain W. 11. Hall,
arrived at Spithead yesterday morning, from Cork. It
was reported that the defects in her machinery would
net be completed before the Gth of July, but the Admi
ralty ordered her peremptorily to Spithead, whether her
defects were repaired or not; and if she could not steam
she was to use her sails, which she did, and which she
can do with facility under the able command of Captain
HAL who deserves a better fate than the drudgery of
this beast of a steamer, miscalled a frigate. She is now
ordered to have ker defects made good with as much
dispatch as possible, and is placed under the commar:d
in chief of S:r C. Napier.
Captain Horatio Austin, C.D., does not proceed to sea
with the squadron. lie commissions the Birkenhead
(and takes his crew from the Blenheim) as the steam
guardship of the ordinary, and will continue his duties
in looking after the reserve steam squadron.
MEN .or WAR SCREW STEAM VESSELS.—We are glad
to find that we are at length usefully advancing, instead
of retrograding in the expel intents which are daily ben.g,
made in the application of screw machinery to vessels
of war. The progress has been of late, as it ought to
be, a gradual development of the excellence of a novel
power of propulsion, and what has been attempted step
by step has been secured, and will form an invaluable
data for working out the same perfection in screw-
steaming as has been,attained in the use of the paddle-
wheel. This must he a source of congratulation to all
who hare of late years been accustomed to see so
many hundreds of thousands of the public money
thrown away on useless and absurd unscientific ex-
periments. We hare at last some satisfaction in expen-
diture—some encouragement from the past to hope for
the future. We have emerged from gross and expensive
blundering and conceited empiricism into something like
a clear and defined course, pursuing which carefully,
steadily, and economically, supported by sound theory,
guided by practice anti warned by experience, we may
justly anticipate results of an important and valuable
character. It is impossible to estimate too highly what
was commenced in the Arrphion, now at Spithead; to
this vessel was applied the first great scheme of auxiliary
propulsion by means of the screw—the ship, it being
remembered, not at all adapted for the purposes for
which she was appropriated, but selected to try 300-
horse power, screw machinery on Count Rosen's prin-
ciple. The pains which have been taken by various par-
ties to work out the knotty problem of success in this vessel
are beyond all pecuniary reward or even appreciation, es-
especially when it is known that the prejudices of naval
officers, as well as engineers, who certainly ought to
have known better, or to have been more liberal, were
perhaps more difficult to be allayed or dissipated than
even the working of the machinery itself. To the honour
and credit of Mr. Miller, however, the senior of the firm
of Miller, Ravenhill, and Co., who manufactured and
matured the engines, and who, although in very b.d
health, did not hesitate to endure all the miseries of an
ill-conditioned man-of- war to superintend the experi-
ments on board the Amphion, to Mr. F. P. Smith, the
projector of the screw propeller; and last, but not least,
to Mr. Dinner', inspector of steam machinery affrat, and
who established the success of the experiments, the ever-
lasting gratitude of the scientific world, and the
thanks of the Government are most justly due. They
were the pioneers in this great work, and the Am-
phion is the ship that has laid the foundation fur
that mighty success which is shadowed forth in the
working of the Encounter, sloop, the second large ship
which has been tried with advantage and credit.
In our former notices of the Encounter we have stated

that she was designed by Mr. Fincham, of Portsmouth
dockyard. She is 895 tens, and has engines of 360
horse-power, by Messrs. Pen and Co., and yesterday we
spoke of the compactness of the machinery, and the rate
of her speed on the passage to Portsmouth from Wool-
wich. This vessel is indeed a wonderful instance of
what has been accomplished in the improvement of both
vessel and engines. She was tried several times on the
river with the most gratifying results. On the last trial
in the river, immersed with weights equal to her stores
and armament, she attained an average speed of 11
knots, the engines having cylinders 60 inches diameter,
with a stroke of 2 feet 3 in., making 78 revolutions, with
a screw 12 feet 6 in. in diameter, and 16 feet pitch; and
this speed with another and better adapted screw, she
has maintained within half a knot on a sea passage, the
ship too having comparatively, for a steamer, a bluff
bow, as is ❑ecessary for men of war to possess.
A third large ship is now about to come into the field
of experiment, and this vessel is the frigate Dauntless.
She was built by the same naval architect (Fincham),
i but that extreme portion of her stern in which the pro-
peller is placed, instead of being finely shaped away as
that of the Encounter, is square, and thus in her case it
is proved beyond question that with a square truck,
although with lines generally good and well adapted for
a screw-steamer, she cannot attain that speed which the
Encounter with a finer run has acquired; for although
the Dauntless has engines of 580 horse•power to 1,496
tons, or 1 to 2.58, the highest mean rate of speed On
trial was not beyond 7i knots. We have accounted for
the difference between this vessel and the Encounter to
some extent ; but it will be a subject of inquiry whether
or not the description of engine has not likewise some-
thing to do with the results.
We may repeat, however, with this short notice of
screw-steam-vessels, that we seem at length to be pro-
gressing in a satisfactory manner, and to acquire uounds
for continuing our experiments to the attainment of that
perfection in steam machinery for vessels adapted for war
purposes, which it is so desirable fur this country to
possess.
The Reynard, screw schooner, is not yet commissioned
by Commander Cracroft. Her engines, wo hear, are
fitted with much compactness by Messrs. Rennie, whilst
many improvements suggested by Mr. Humphries, the
superintendent of their factory, have added much to her
completeness. By au ingenious contrivance of Mr.
Humphries, the screw propeller is lifted out of its posi-
tion with the greatest facility at the will of the engineer
in the engine. room. On trial, yesterday, the time oc-
cupied in lifting the screw rudder three feet out of the
water was 2i minutes, and on one occasion 1k minute.