The Sun.
London, England, 1864-12-30 00:00:00

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NEWSPAPER
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Naval and Military IlLti4ll'"
\ • Y fLir,3 esterday the operations of fixing ‘tite.fit4-of
armour-plates to the sides of the irdaladitgaa
frigate Bellerophon, 14, 2;240 tons, 1,000 horse
power was commenced in the second dock at Chats
ham, in which that vessel is under construction,
and' the work of bolting the thousand tons and up-
wards of armour to the exterior of the frigate will
be proceeded with as rapidly as the resources of
the dockyard will permit. The plate fixed to the
midship starboard aides yesterday was one of thew
supplied by the Millwali Iron Company, to which
firm has been confided the task of preparing the
armour-plates required for the vessel. It is.one cf
the best rolled iron, and weighs nearly seven tons,
its dimensions being 16 t. in length by four feet
in breadth, and Gin. in thickness, the uniform thelas
ness of the armour-plates carried by the Bellern-
phon along both sides of her midst-Apo battery. lie
Warrior, Achilles, end Black Prince will be prcs
vided with plates of 4:n. only. lo addition, how-
ever, to the extra thickness of armour-plating given
to the Bellerophon, her inner or skin plates ere
4in. in thickness, which is nearly en inch in excess
of the inside plates of the Achilles, the latter frigate
having her inner plates worked to 9 I'3ths of an
inch only in thickness. BeeNeem the outer and
inner plates of the Bellerophon, however, the
timber backing has been very materally reduced,
the planking to which the armour plates are at.
tacked being only 10in. in thickness, the additional
couple of inches in the thickness of iron which
cover her sides being considered more than an equi-
valent for the reduction effected in the wooden
backing. In the Bellerophon it will thus be seen
that shot and shell will have to penetrate riin of
solid iron and the teak backing, while in the
Minotaur_ the -thickness of armour plating and
inner plates is but six inches, and in the
Warrior only five. The bolts far securing the
plates to the sides of the frigate are prepared at
Chatham dockyard, where arrangements have also
been completed for galvanising them, without in-
curring the delay experienced in the construction of
the Achilles by sending the bolts from the dockyard
to London to be galvanised by a private firm, and
afterwards received back at the dockyard. Expea
rience would seem to prove, however, that little real
advantage is obtained from the use of galvanised
bolts, end it is therefore at present intended to disc
pense with that process in the case of the Bellero-
phon by the use of the ordinary bolts of 2lin. in
thickness. Six steam cranes are constantly em-
ployed alongside the Bellerophon dock in lifting the
iron required for that vessel, and two more, of cons
siderably larger dimensions, are now being erected
alongside by Messrs Taylor and Co., of the Bri-
tannia Works, Birkenhead, for hoisting the armour
plates to their place. In the construction of
the iron frigate the utmost energy is being shown,
and as an instance of the rapidity with which
she is being built, it may he stated that the first
piece of iron for her keel was lowered into the dock
on the Bth of April last, and she is now sufficiently
advanced to receive her armour plates. From her
present rate of progress she will be completed and
afloat before the close of the approaching year, the
Bellerophon in this respect presenting a remarkable
contrast to the Achilles, which was constructed in
the same deck.

The irun frigate Achilles, Captain E. Vansittart,
remained at Spithead yesterday, awaiting orders
from the Admiralty, who it is anticipated will
direct her to proceed to Davouport to be docked
and replace her damaged propeller with a perfLet
one. The diver who has been sent down to examine
the ship reports two out of the four blades of the
screw to be broken off from the boss, bat no other
damage is visible. The suddenly accelerated speed
of the Achilles' engines on the loss of these two
out of her four screw blades, to which we re-
ferred in The Sun of yesterday, when noticing the
accident, is just one of those circumstances that is
always attended with the greatest possible danger
to the engines where no certain mechanical self-
acting control is applied for the admission of steam
to them according to the actual amount of work
being done by the propeller. Na accident did occur
to the engines of the Achilles on Wednesday by
their suddenly increased number of revolutions, con•
sequent upon the loss of her propeller blades; but
the fact remains that serious danger for tome mo-
ments did exist from the " racing" of the engines,
and serious damage to the machinery w,s in all
probehility only averted by the prompt measures
taken by the officers in charge of the ermine-room.
There are two sets of conditions under which all
steamships are liable to damage seriously their ma-
chinery when under full steaming power by the sud-
den " racing" of their engines. One is when a ship,
like the Achilles, suddenly throws off a portion of
the driving surface of her propeller; the other is
when a ship under steam, in a heavy or following
sea, lifts her stern, and with her stern her screw also,
occasionally out of the water. In such cases the
engines " race," to use the technical phrase, by the
loss of resistance on the driving faces of the screws
blades, and the danger to the ship's engines is al.
ways imminent under such circumstances, and can
only be averted as was done, happily in the Achilles
by a prompt attention to the throttleavalve, or the
accident really occurs as it did to the Himalaya by
the racing of the engines, as the ship, running at
tremendous speed on her return to England from her
last foreign voyage, lifted her stern to the seas and
with it propeller clear of the water. We have ex-
plained how the Achilles escaped accident to her max
chinery, but the Himalaya cracked her shaft
through, and will lie a useless ship for at least three
month in Portsmouth harbour before she can again
be made! ready for sea. In the mercantile steam
navy this danger to engines is very effectually met
by the application of a "governor," which regulates
the admission of steam to the cylinders, in accord•
ance with the actual work done by the propeller.
The " Silver governor" is generally admitted to be
the best contrivance of the kind, and it is already
fitted on board upwards of 300 vessels in the mere
cantile navy. The apparatus is extremely simple
and effective. So long as the engines run at a unit
form rate of speed the governor gives the steam free
admission to the engines; but the slightest deviation
from this uniformity of motion closes the throttle•
valve and stops the supply of steam until the engines
resume their even motion.
In our report of the first trial of the Achilles at
Portsmouth, which appeared in The Sun of the 15th
inst., the ship's propeller was described as being " a
fourebladed Mangin." This is now explained to
have been an error. The screw of the Achilles has
its four blades set round the boss at equi.distant
intervals, singly, but Nos. 1 and 3 blades slightly
in advance of Nos. 2 and 4. The ordinary Mangin
screw has its four blades set on the propeller boss in

pairs.
The following appointments were made yesterday
at the Admiralty :—Lieut. Thomas Ramsbotham to
the Royal Adelaide—R, D. Clements, midshipman,
to the Hector—Geo, B. Long, naval cadet, to the
Achilles—Henry D. Philips, nominated to a naval
cadetship—Geo. H. Ryan, surgeon, to the Shannon
—and Jas, C. Meagher, paymaster, to the Meander.

Foreign Mail Packet List.

MAILS DUE.

Australia and Mauritius, via Southampton. ...... Jan. 18.
via Marseilles'......... Jan. 12.
Brazil and Cape Verde, by British packet........ Jan. b.
Cape of Good Hope, Ascension, and St. Helena., Dec. 29.
china, Penang, and Singapore, Nia Southanipton.Jan. 2.
_ _ via Marseilles ...Dee. 27.

Falkland Islands . ......... _......
Gibraltar, via Southamptt ,t Dec 27.
India (Calcutta), and Ceylon, via Southampton Jan. 2
via Marsoille Dec, 27.
India (Bombay), via Southampton ...... Dec. 27.
via Marseilles Dec. --.
Portugal • .. •
Malta, Egypt, anti A den, via Southampton Dcc. '27.
via Mareeilles Dec, ,
Newfoundland
Oporto and Vigo ... .........
U. S. and British N. Amorica, Ly Brit. packet... , Dec 29.
by U.S. packet.... _
. _ _

.
I.v Canadian paCliCt:Dec. 20.
W.C. of Africa, Madeira, and Teneriffe .Jan. 10.
West Indies and Pacific , Dec. 29.
Bahamas (via New York)
Bermuda (ditto) ...Jan. 18.
Cuba and Mexico ..Dec. 29.

The only other steamer to arrive from New York
this week is the Glasgow, which sailed on the same day as
the Hanes. No later news is likely to be received before
Monday, the next Cunard steamer being the Canada from
Boston, which was to sail on the 21st,