The Sun.
London, England, 1856-10-14 00:00:00

Naval and Military Intethgence.

DEATH OF COMMANDER CHARLES
THURTELL.
We announced reeterday the death of Commander
Charles Thurtell (184_3), which occurred lately at Calais.
He was born at Bradwell, Suffolk, on Feb. 29, 1790.
We extract the following account of the services of this
gallant officer from " O'Byrne'a Naval Biography :''-
‘ This officer entered the navy March 26, 1807, as
first-class volunteer on board the Alert, Captain Robert
Williams : and in the course of the same year was pre-
sent, under Admiral Gasebier, in the attack upon Copen-
hagen. In May, 1800, five months after he bad left the
Alert, he joined the Aboukir, 74, Captain George Parker
and Thos. Browne, in which ship we find him accom-
panying the expedition ition to the Scheldt (where he was en-
trusted with ',;he command of a gun boat), and emol,yed
in 1812 une,er the flag of the present Sir Thomas Byam
Martin, at the defence of Riga. He there had charge of
a Russian gun boat, and was for three months in almost
daily action with the enemy. In November, 1812, he
was nominated acting master of the Briseis, 10, Captain
John Ross, in the Baltic ; he served next, from Nov.,
1813, until May, 1815, as midshipman and master's mate,
in the Nymphen, 36, and Liffey, 50, both commanded by
Captain John Hancock, on the North Sea and Channel
stations ; and in March, 1817, and September, 1818, he
became Admiralty midshipman of the Cadmus, 10, Capt.
Tohn :Judge, again in the North Sea, and Rochfort, 80,
bearing the flags of Sir Thomas Francis Fremantle and
Graham Moore, in the Mediterranean. At the gene-
ral promotion in 1815, notwithstanding that a very ur-
gent request was made in his favour to the First Lord
of the Admiralty by the magistrates of the city of Nor-
wich, Mr. Thurtell was passed over ; nor did he succeed
in obtaining a commission until October, 1821, when,
being at the top of the Admiralty list in the Mediter-
ranean, he was appointed to a vacancy in the Medina,
20, Captains the Earl of Huntingdon, Richard Ander-
son, and Patrick Duff Henry Hay. In September,
1820, being at the time in command of the Racer cutter,
tender to the Rochlort, he was directed by Commodore
Hon. Anthony Maitland, of the Glasgow, 50, then at
Malta, to proceed to Palermo with a despatch for Cap-
tain John Donaldson Boman, of the Spey, 20, and in
the event of not finding him at that place, to repair
forthwith to the port of Messina, and thence to return
to Malts. On his arrival at Palermo, not meeting with
the Spey, and the city being in a state of insurrection,
and closely besieged by the Neapolitan naval and mili-
tary forces, who were hourly expected to carry it by
storm, he received through the hands of her Britannic
Majesty's consul general an address, couched in the
strongest;terms, from the English merchants and other
residents, entreating that at a motnent of such distress
he would remain by them, and afford them such protec-
tion as he could. With this solicitation he felt it his
duty, under the circumstances, to comply. By his spi-
rited interference he obtained from General Pepe, the
Neapolitan commander in chief, permission for the British
to seek safety either in his camp or on board the men of
war in the bay. The Racer afterwards, at the request
of the chiefs of the contending parties, became the theatre
on which, as the only neutral spot open to them, they
entered into and concluded a treaty of peace. The mo-
ment the ratification was signed, she announced the
joyful intelligence by a Royal salute-a salute which was
returned by the Neapolitan fleet and all the forts. The
zeal and exertions thus displayed by Mr. Thurtell, and
the important services he rendered, in a situation in
-which no midshipman was perhaps ever before placed, ob-
tained him the grateful thanks as well of the British re-
sidents as of General Pepe and of Prince Patterno, pre-
sident of the Provisional Junta of Palermo. The history
of his proceedings was made the subject of a special commu
nication to the Foreign Office by the present Lord Heytes-
bury, then ambassador at the Court of Naples ; but, owing
to the circumstance, perhaps, of no official representation
being made of them at the Admiralty, he received not
the least reward. His appointments after he left the
Medina were-July 24, 1822, and May 3, 1824, as first,
to the Chanticleer, 10, and Dispatch, 13, Captains Bar-
tell Macnamara and Edw. Hinton Scott, both In the
Mediterranean, whence he returned at the close of 1824;
S ept. 14, 1839, to the San Josef, 110, bearing the flags
at Plymouth of Admirals Superintendent Fred. Warren
And Sir Sam. Pym ; and Sept. 26, 1842, again as first,
to the Caledonia, 120, bearing the flag of Sir David
commander in chief at the same port. He was
advanced to his present rank Jan. 12, 1843, and has
since been on half-pay.

"Remindful of his former services the Xing of Na-
ples, in 1838, made an application to Government for
the promdtion of Mr. Thurtell ; and at other times the
corporation of N6rwich, the Attorney. General (Sir R.
Grant), the Dukes of Devonshire and Leeds, Admiral
Sir E. Codrington, and other distinguished personages,
similarly interested themselves in bis behalf."

The reports from Malta, reaching to the Dth of Oct.,
notice the following movements, chiefly confined to mail
steamers and merchant steamvessels :

" The Peninsula and Oriental Company's steampacket
Valetta arrived from Alexandria on the 28th Sept , wit:,
the overland India mail for England, which she carried
on to Marseilles on the same evening, conveying Colonel
Campbell, Captains Bray, Blackwood, Luxmore, and
Pritchard ; Lieuts. Lamb, Macaulay, and Southey ; and
from Malta, Mrs. Gen. Williams and Lieut.. Colonel
Sankey, late in the Ottoman service.
"The Indus, belonging to he same company, arrived
from Alexandria with the heavy mails on the 29th, and
left on the same day for Southampton, conveying Col.
Doherty, Major and Mrs. West, Major and Mrs. Dyver-
net, and Commander Parker, R.N. She also conveyed
from Malta Quartermaster Leech, of the Anglo-Italian
Legion.

"The Colombo screw steampacket, belonging to the
same company, arrived from Southampton and Gibraltar
on the 29th with the outwari India mails, bringing, for
Malta, Captain Pennefather, and for Alexandria, Major-
General Wilkinson, Colonels Cotton, Steel, Stuart and
wife ; Lieut.-Colonel Grant and wife ; Majors Hill,
North, Buller and wife ; Captains Bowie, Sbuttleworth,
Walker, and Waterman ; Lients. Ashburner, Martineau,
Hamilton, Wilkinson and wife; Ensigns Stuart and
Mason ; Dr. Morrogh and wife.
" The Vectis, Peninsular and Oriental Co.'s steamer,
with the overland London mails of the 26th of Sept.,
arrived on the Ist of Oct., bringing for Alexandria, Col.
Cotton, Lient.-Col. Taylor, Major Payne, Major and
Mrs. Prescott, Captain Ireland, Captain Brown, Cap-
tain Kemball, Lieats. Bearsley, Kennier, Davison. and
wife, Playfair and wife. The Colombo and the Vectis
left for Alexandria on the Ist of Oct.
"The Simoies French postal steamer arrived on the
28th from Marseilles, bringing, among other passengers,
Capt. Baynes, B,h, and Deputy-Assistant CommisQary•
General Arthur Baynes, for Malta. She left for Syra,
Smyrna, and Constantinople on the same evening,
whence the Carmel French postal steamer arrived on the
evening of the 30th of September, bringing Lieut,Col.
Morgan, Osmanli Irregular Cavalry, for Malta, and
Captain Harris for Marseilles, for which pert she pro-
ceeded on the Ist of October.

"The Indus and the Meandre, French postal steamers,
arrived from Marseilles on the sth, the former convey-
ing, among other passengers for Alexandria, for which
destination she left the same evening, Mdlle. Rachel,
accompanied by her sister, seeking a change of climate
at Cairo. The Meandre left at the same time for Syra,
Smyrna, and Constantinople, after landing at Malta
Capt. Taafa, Ist Royals, Major-General Warren, Capt.
St. John, 92d, Aide-de-Camp, wife and family.
" The Vatican French postal steamer arrived from
the Italian ports, and Messina, on the sth,
bringing, among other passengers for Malta, Dr. Waite,
47th, Mrs. (Commissary-General) Wild and family.
" her Majesty's steam packet Oberon arrived on the
Ith front Corfu and Zante with the mails.
" The Malta steamer arrived c re the 2d from Liverpoul
and Gibraltar, arid left for Constantinople on the 3i.
" Her Majesty's screw stearathip of the line Cressy
arrived from England and Gibraltar on tho 3d.
" His Netherlaed's Majesty's frigate Daggersbank ar-
rived on the 3d from the Texel, and immediately after
anchoring exchanged salutes with the garrison and the
flag of Rear-Admiral Sir H. Stewart. On the same morn-
ing her commander, the Baron Collet D'Escury, accom-
panied by the Chevalier Stevens, the acting Netherlands
consul at Malta, visited Rear-Admiral the Hon Sir M.
Stopford, the Admiral Superintendent of the Dockyard,
and likewise his Excellency the Governor, Sir W. Reid.
On the Gth she took her departure for Smyrna and
Alexandria.
"Her Majesty's steamtug Wallace left for Cerigo on
the 4th with the new light to be erected on that island.
"The Durance French screw steam transport arrived
on the 30th from Toulon, and left for Toulon on the sth."
Two companies of the 4th battalion of the Royal Artil-
lery, under orders for Portsmouth and Devenport, as well
as detachments to other home stations, were yesterday
morning officially inspected at Woolwich by the com-
mandant of the garrison, Major-General Williams and
staff. Lieut.-Colonel Mande, R.A., has returned to
head-quarters, Woolwich, from his attendance at the
coronation of the Emperor of Russia. Colonel' Eardley
Wilmot,
13.4., and Mr. Abel, cf the Laboratory De-
partment of the Royal Arsenal at Woolwich, have like-
wisreturned from their mission to Silesia, in Western
Prussia,
Which was undertaken with a view of iespectine
the iron fOundkies of that country, and investigating the
mode,
of smelting by means of gas, which is pronounced-
to be more successful than charcoal The freight ship Nautilushas been ordered to Deptford
to embark provisions and naval stores.
fSrhoeniwWill°reltwuirenito Woolwich to ship 150 tons of ammuni-
tion, and is to sail thence on Saturday next for Bermuda.
The freight ship c perdovvn has arrived at Woolwich
from the London Docks, and has commenced shipping
700 tons of ordnance store for Bermuda.
The transport Preciosa
has
fromwith
a cargo of ordnance stores and 1 ,
the East. made by the officers
Chatham
Extensive preparations are being
and troops belonging to garrison in conse-
(pence of permission having been accorded them by the
authorities to have a variety of athletic sgporritztie,s,gwarcih,
and foot races on Chatham-lines, for various
are to be contended for exclusively by the
soldiers stationed at Chatham. The Poffice. officers and
sports %ft ::71:.te.
p!ace (weather permitting) on Thursday afternoe,
1,7
and considerable interest is felt is the undertr-''7--..
the officers of the garneee this being the fi=st
to provide amusements of this kind for the trcopS
rt
Chathath. The spode will be under the patronage
_ct
Colonel Eden, Commandant of the garrison, and tho
offieere who have been successful in getting up the amuse-
ments are Major H. Marriott, R.M., Major S. G. Ban-
kery, Medical Staff Corps, Major C. S. S. E. Gordon,
Lyons, sth Fusiliers, Capt.
Brigade Major, Captain W.
Fitzroy Somerset, and Captain F. Brine, Royal En-
gineers, A grand stand is to be erected on Chatham
lines, where the sports will take place, and the garrison
bands will be in attendance.
He
ntv sloop Daring, 12, Commander Gerald
trpir,h
'val of which at Spithead we briefly re-
ported yesterday, sailed frogs Port Royal, JAraaaer3taje6 a-
6 ka, on

the 27th of August, in company with H.M.S. Espiegle,
12, Commander Lambert (both bound for Spithead) and
parted company with her on the 31st off Cape Maize,
Cuba. Nothing of any importance occurred until the
18th of September, when to the northward of Bermuda
she encountered a heavy hurricane, which increased in
severity till the 20th, when it reached its climax. She
e,'caped with the loss of her sternboat and lifebuoy. For
48 hours she was under bare poles; the ship behaved re-
markably well, although the sea ran very high. The
cutwater started, which crippled her bowsprit a little,
but it was soon got all right again. Her hammock
berthing was partially washed away; in fact it was con-
sidered as hard a gale as had been experienced by any
one on board. She sighted the Lizard on the Bth,
light and foul winds ; passed her Majesty's ship High-
flyer and two gunboats in tow, 30 miles S.W. of the
Lizard. Same day also exchanged numbers with - the
ship Mangerton, of London, and a great many ships out-
ward bound. The Daring has been four years in com-
mission, and haT lost less men than any other ship on the
Jamaica station by sickness or otherwise, She left Spit-
head yesterday afternoon for the eastward to be paid off.
The Espiegle, 12, arrived at Spithead yesterday morning
from the North America and West India station, to be
paid off. She leaves Port-mouth this evening for the
eastward. She spoke on the Bth inst., in lat. 48 34,
long. 6.57, her Majesty's ship Salamander, for Madeira.
The steam troop-ship Urgent, Commander Phillips,
arrived at Portsmouth yesterday from Ireland, with part
of the 33d and 50th Regiment?, which she landed at the
dockyard.
Her Majesty's ship Retribution, 22, Capt. Barker, had
steam up at 6 o'clock last night ready for leaving for the
Meiliterranean.
Her Majesty's steam troop-ship Simone was taken
into dock at Portsmouth yesterday for a refit.
The steam store ship Hesper arrived at Portsmouth,
yesterday from Woolwich to ship stores and medical
comforts for the island of Madeira.

The following appointments were made yesterday at
the Admiralty :—C. W. Talbot, naval cadet, to the Prin-
cess Royal ; C. R. Harris, ditto, to the Colossus ; J.T.
Bedford, ditto, to the Retribution ; R. D. Campbell,
ditto, to the Csar ; E. F. Keppel and U. E. Eyre,
ditto, to the Raleigh, and J. D. Webb, ditto, to the Sa-
tellite.

THE NEW AMERICAN STEAM-SHIPS OP WAR.

The visit of the large American steam-frigate Merri-
mac to Southampton having occasioned considerable
interest we think it may now be a proper time to lay be-
fore our readers such information as we have from time
to time obtained respecting her, and the Wabash, the
Minnesota, the Roanoke, and the Colorada—four ships
of much the same size and power of the Merrimac—
and also respecting the huge steam-corvette the Niagara.
In order to render the information which follows per-
fectly reliable, in so far, at least, as the Merrimac is
concerned, we have visited that vessel, and verified by
personal observation the facts hereafter stated. In mak-
ing this verification we were favoured with the utmost
courtesy and co-operation on the part of the officers of
the ship, and particularly of first lieutenant G. W. Har-
rison, who was in command of her at the time of our
visit, and to whose kindness we are much indebted.

The principal dimensions of the five frigates above
enumerated are so nearly alike that they may, for all
ordinary purposes, be considered the same, and may be
to ken as follows : '

Feet. Ins.
Length of keel
Length on load-water line
Length over all 3OO 0
Breadth extreme
Breadth moulded - 5O 2
Depth of hold (to gun deck) 26 4
Draught of water forward
Draught of water aft

As our examination of the Merrimac was made for the
purpose of estimating her merits as a ship of war, we must
add to the above the following details, which are of im-
portance in such a ship. When the vessel is at her load
line the height of the gun-deck ports above the water
are, amidships, 9 feet, and forward and aft 12 feet, or
thereabouts. The height from her gun deck to the lower
sides of her spar-deck beams is 6 feet. The height of
her bulwarks is such, that when the hammocks are
stowed, they reach 8 feet 8 inches above the upper deck.
Her gun-deck ports are 3 feet 8 inches long, and nearly
8 feet 6 inches apart. Her load displacement is esti-
mated at 4,000 tons ; but this we could not, of course,
I test.

The Merrimac was designed by Mr. Lenthall, who is
at the head of the Bureau at Washington, and was built
by Mr. Delano, the master shipwright of the navy yard
at Boston (or the officer who corresponds to a master
shipwright of our own dockyards). Her frame is of live
oak, crossed on the inside with two sets of diagonal iron
plates, which are inclined in opposite directions. She is
also strengthened by similar plates on the outside, at bow
and stern. Her plank is also of oak, and, like our own
ships of war, she is copper-fastened np to a few feet
above the load-water line. Her decks are of fir. On a
careful inspection, she seems to have been built with
very great skill and care, and is a very tight strong ship.
The large wooden knees (common in American ships,
because more approved of and more readily obtained
than iron) to some extent interfere with the beauty of
her appearance inboard ; but she is a very roomy and
handsome ship, and the appearance of her main deck is
unsurpassed.
With all her sails set, she spreads 56,629 square feet
of canvas. Her engines are auxiliary only. Her rig is
in all respects like that of the largest American sailing
frigates, but from her great length she seems capable of
carrying masts, spars, and sails even larger than those
she has. The mode in which the mainmast steps is
worthy of attention. The shaft of the propeller coming
immediately beneath it (since the engines are before the
mainmast), a step is formed to receive it above the shaft.
This step consists of a large thwartship beam of live oak,
supported near the middle by two 12-inch solid iron
columns which rest upon suitable keelsons. This ar-
rangement is perhaps as good as any other, although the
strength attending it must certainly be much less, than
that in which the mast steps in a wooden step, sup-
ported immediately by the keelsons themselves, as is the
case where no screw shaft interferes. The modes adopted
in our own navy are various. In some cases tall forked
iron steps, which stride across the shaft, are employed,
and is others the heel of the mast itself is enlarged, and
the shaft allowed to pass through it, the lower piece of
the mast being separable from the upper, and connected
with it by clasped jointed hoops.
The Merrimac is pierced for 60 guns, but if she were
actually to carry that number they would have to be of
a lighter character than those now on board of her. Her
present armament is as follows :—On her upper deck
there are two large pivot gun:, each weighirg nearly 51
tons, and of 10 inches bore, and 14 8-inch guns, eacti
weighing rather more than 3 tons ; on her gundeck there
are 24 9-inch guns, each weighing nearly 4.1 j tone. The
whole of these guns, 40 in all, though strong enough to
discharge shot, if desired, are primarily intended to be
served with hollow shot or with shell--for it is now a
practice with the Americans to supply their navy with
a quantity of empty hollow shot, which may be either
plugged and used as eucb, or charged, fitted with fuzes,
and used as shells. We must not, however, omit to
mention that she might carry a few additional 9 inch
guns on the main deck with perfect convenience. Her
gun-carriages on the main deck are similar to those used
in the French navy, They have, however, bat two wheels
or trucks each, at the ship's end of the carriage. To
facilitate the running out of the gun the rear end ef the
carriage is raised by a handspike fitted with a roller at
the end, on which roller the carriage runs out. At the
upper side of this handspike roller is a pin or stud which
takes into one or other of a series of recesses formed in
a plate on the underside of the rear end of the carriage.
The carriage slides of the large pivot guns differ from
our own chiefly in the fact that they are furnished at
each end with wheels or trucks (which run on the metal
circular bearing plates on the deck) mounted on
eccentric axles. Those axles are turned by a spanner,
so as either to take the weight of the slide and allow
it to be run round upon them, or to he raised clear
of the bottom of the slide, and allow it to rest imme-
diately upon the deck plates. The carriages which run
upon the slides have their rear trucks mounted upon
similar eccentric axles. The friction of the carriage upon
the slide when the piece is to be discharged (and when
the trucks are clear of the slide) is sometimes increased
by nipping the two together with screws.
The whole of the 9-inch guns, or main-deck guns, as
well as the two 10-inch pivot buns, are formed on Com-
mander Dahlgren's system, which consists in giving to
the gun, at each point of its length, a thickness propor-
tioned to the direct pressure of the powder in the chase
at that point, supposing the gun to be fired with au ordi-
nary service charge. In order to carry out that principle
Commander (then Lieutenant)Dahlgren took an ordinary
Paishan gun, and had bored in it a number of holes, each
of the Pize of a musket hall, extending from the outside
of the gun through into the chase. These holes were per-
pendicular to the axis of the gun. A musket ball was
then placed in the first hole (the rest of the holes being
Plugged for the time), the gun fired with a service charge,
and the initial velocity communicated to the musket ball
measured by a ballistic pendulum. This was repeated
with each hole successively, and lines representing the
initial velocities thus obtained were taken as the ordi-
nates of a curve (of which the distances apart of the
holes reprecented the abecisF.), and this curve gave the
contour of the exterior of the gun. The Dahlgren guns
are of greatly increased thickuese along the chase, and
Fluddenly increase their thickness near the breech, where
the great bulk of the metal of the gun is collected.
Before the adoption of them in their navy, the Ameri-
can Government had them severely tested, with highly
eetisfactory results. Witliem. doebt the principle of
I Commander Dahlgren is corvect, eo Mr as it oes. There
are ale-eellateral advantages connected with the adop- '
tine of it in naval ordnance, one of which is that the
' centre of gravity of each side battery iz-, owing to the
form of the curse, thereby brought nearer to the middle
of the ship, which muse tend to make her roll less hea-
vily than otherwise. Each gun is furnished with two
lock-lugs, or lugs for the gun-lock--one for use, and one
to supply its place if it should be knecked away.
There are a few other novel features in connection
with the guns of the Merrimac. One is that her guns
are fitted with elevating screws, which supply the place
of the quoin, &c., in our own service. This arrangement
tends greatly to facilitate the sighting, and is certainly
an improvement, provided that it is not attended with
any defect in strength, and were assured that none had
been observed during considerable practice. Another

new feature is the employment of bristles, instead of
sheepskin, in all the sponges and raminers for the guns;
and a further one is the employment, for boat guns, of
light and elegant wrought iron carriages, of which she
has three—one for a 9-pounder, a second for a 12
pounder, and a third for a 24 pounder.
The engines of the Merrimac are by Mr. Parrott,
of the Cold Springs Foundry, New York. She has
two cylinders 72 inches in diameter, and three feet
stroke. These are placed close to the shaft, on oppo-
site sides of it, leaving room only for the crank.
Each piston has two piston-rods, one above and one be-
low the shaft ; these carry a crosshead, from which the
connecting rod reaches back to the crank, as is well un-
derstood by the engineers. Each cylinder has its con-
denser at the side of it, and its air-pump opposite to it.
The air-pump rods go through the cylinder ends direct
to the piston. She is fitted with four of the vertical
tubular boilers, patented by Mr. D. B. Martin, engineer
in chief of the United States navy, similar to those fitted
previously in the Su,quehanna, by Merrick and Son, of
Philadelphia. The boilers are of iron, with brass tubes,
and have the following general dimensions :
Length of each boiler, athwart ships, 11 feet ; breadth,
fore and aft, 14.8 feet ; length of vessel occupied by four
boilers, 31 feet 8 inches ; breadth of ditto and fire-room,
31 feet. The fire-room is between the two pair of boil
ers, the furnaces firing athwart ships, and the flues de-
livering into one chimney. Height of boilers, 13 feet 6
inches ; cubical space occupied by all the boilers and fire-
room, being the content of a parallelopipedon included
within the above circumscribing lines, 13,240 cubic feet ;
number of furnaces in all boilers, 16 ; breadth of ditto,
each, 2 feet 101 inches ; length of ditto, each 7 feet ;
grate surface ares, in all, 338 square feet ; number
of tubes in all boilers, 5,480 ; length (or height) 374 in. ;
diameter (outside) of the tubes, 2 inches ; heating surface
in furnaces and back connections up to tuhes, 1,614
square feet ; heating surface in tube boxes, 8,508 square
feet ; heating surface in tube boxes, and connections to
smoke chimney, 1,581 square feet; total heating surface in
all boilers, 11,703 square feet ; proportion of the same to
grate area 34.6 to 1.00; flue area or calorimeter between
tubes in all boilers, 42 square feet ; proportion of the
same to grate area, 1 to 8 square feet ; diameter of smoke
chimney, 8 feet.
The boilers all have water-bottoms, with not less than
6 inches of water space at any point ; back of the furnaces
these bottoms rise to the back connections; the tube boxes
are above the furnaces, and rise about 3 inches to the
front end of the boiler, where they enter the front con-
nections. The boilers are of 3-Bth inch, and inch best
American plates, double riveted and caulked inside and
*lst, throughout, and are well braced. The weinht of all
four, when empty, is 255,0001 b. Their total weight, when
filled to the working level, is 440,0001 b.
To test the economical evaporative efficiency of this
form of boiler an experiment was made on the 13th of
March last, in the presence of several engineers of the
navy, the conditions and results of which were, as pub
lished by Mr. Merrick, the maker, as follow :
Two boilers only were used, and the dampers were
nearly closed.
The coal used was anthracite, and of an inferior qua-
lity. Toe engines are fitted with Stevens's cut-off, which
was adjusted and permanently fixed to cut off as follows:
Port engine, one end

If
fl
Starboard engine, one end

4.12
. 4.60
3.35
Average per indicator-card, with full throttle 3.97 feet.
Adding to this the average clearance at each
end of the cylinder, and including, also,
the steam passage, &c., between valves and
cylinder, equal to 23.820 cubic inches, or
the area of the cylinder by 6.05 inches of
stroke, or

.504 feet.

Average length of cylinder, filled at each
single stroke
Preserving the same level of water in the boilers, and
(as nearly as could be ascertained) the same quantity of
coal in the furnace, or about the same fires, and main•
taining the same pressure of steam, 4,2001 b. of coal were
consumed, and 1,615 new revolutions made and noted by
register, the duration of the experiment being 3 hours
57 minutes. During this time 11 double cards were taken
on the two engines, which showed a mean pressure of
steam entering the cylinders, during that part of the
stroke over which steam was admitted, of—

Total pressure—Port engine, 18.991 b • starboard en-
gine 21.811 b, of which (Pambour) the volume is 1257.
Hence the water evaporated during the experiment
was as follows :—the two cylinders being 70 in. dia-
meter =26.41 square feet of area,

26.71 x 4.474 x 1615 x 4x 62.5
1257 =39,3721b of water,
which, being evaporated by 4,200 lb of coal, gave 9,137
lb of water per lb of fuel.

The temperature of the hot well was 891 deg., and of
the feed-water entering the boiler at (probably) 85 deg.
The evaporative power of the boilers will at once be
seen from the above figures of Mr. Merrick. In the
Merrimac very excellent results have also been obtained
with Mr. Martin's boilers. Her coal bunkers carry
about 600 tons of coal. A small pair of donkey engines
are provided on the main deck for coaling, raising heavy
weights on board, &c. These auxiliary engines have a
suitable boiler to supply them when the main boilers
are not at work. The steam pumps are fitted in connec-
tion with the large engines for pumping out the bilge,
extinguishing fires, &c. These steam pumps may be sup.
plied, with steam from the auxiliary boiler, if desired.
The Merrimac is fitted with a Griffith's screw propeller,
with means of varying the pitch. In this respect she
differs from her sister ships, all of which have ordinary
propellers.
The Niagara is, we underotand, to Lave a
Griffith's.

The propelling arrangements on board the Merrimac
are very complete. The forward thrust is taken by a
series of c)llars, and the backward thrust by a brass disc
dropped down between the end of the propeller bearing
and the after sternpost. This disc may be readily re-
newed when worn. The shaft is supported between the
engines and the dead wood by bearings and intermediate
spring supports, and a cooling pipe is led from the out-
side of the ship ever each. The after-propeller bearings
are of wood, upon Penn's principle. The propelleris raised
by a cable and pulleys, the cable leading to the capstan.
A long wooden stay, tightened by a screw, is used for
keeping the propeller down in its place, and figitable
means are also provided for steadying the propeller dur-
jug the raising of it, for slinging it when raised or parti-
ally raised, &c.
The greatest speed ever attained by the Merrimac
under steam alone was seven knots per hour, and this
was made under very favourable circumstances. Her
average steaming speed is much less than this. There
are, however, certain defects in connection with her
slide valves which prevent the full and most economical
results being attained with her engines. The lap and
lead was so small that at first she could not cut off her
steam until 19 inches of her stroke. She will, for the
suture, owing to improvements made on board, cut off
at 15 inches. But radical changes must be made in
her valves before the necessary economy is obtained.
The details of the engines—the driving gear,
&c.—are very well arranged. _ _

The Merrimac is full of evidences that the American
Government are willing to give trial to improvements of
a promising ehara,ete: in their ships of war, notwith-
standing the changes which their introduction renders
necessary. At the same time there aro arrangements,
which have been proved highly valuable i❑ our own
service, nnadopted by them. For example, instead of
the admirable lightning conductors of Sir W. Snow Har-
ris, used with so much advantage by 114, the old bit of
chain long discarded here, lies down against her shrouds,
and gives great offence to the eye of the intelligent visi-
tor. _air, on the whale, the useful improvements
greatly out-number the defects. This we might show
at :reat length if we thought it desirable. It will, how-
ever, he sufficient to add a further fact or two. The fish-
davit is centred on a hoop on the foremast, and may be
s sung ever either anchor for fishing. it, and may also be
usad to assist in the removal of the heavy berthing
which has to be taken down when the bow pivot
gun is used. Both operations may be performed by
steam power derived from the auxiliary engines. An-
other useful arrangement is the use of a hinged tongue-
piece, which may be pressed clown between the links of
the cable by a screw when the ctble has to be fleeted.
Another is the employment of light bulk-heads around
the engine-room hatches on the main deck. Whether
the absence of all mess tables for the ship's crew is an
improvement or an act of retrogression we leave our
naval officers to decide.

In our next number we shall probably publish a few
further statements respecting the Merrimac. At-the same
time we believe that the points of chief importance are
included in the above remarlci.

The Niagara is built, we are told, as an experiment ;
and it is perfectly certain that if she should prove a tho-
roughly strung and efficient ship of war, she will surprise
everyone who has hitherto been considered well informed
on the nature and requirements of war ships. The his-
tory of this ship's origin is simply this :—Mr. Steers, of
New York, built the America yacht, which proved to be
a very fast one. Tole gained him reputation and friend
and secured him orders for constructing various other
vessels of largersizes. He succeeded in building more than
ore fast and serviceable commercial steam ship, and when
the American Government resolved upon making a de-
monitration with large steam ships of war, Mr. Steers, or
the friends of Mr. Steers, succeeded in getting the design
and construction of one committed to him. Mr. Steers
knew but little, if anything, practically of ships of war,
and, if we are rightly informed, cared to know but little
of them, except what the light of nature supplied him
with, for we are told he availed himself but very little
of the freedom with which he was permitted to have
a'ccess to the bureau of construction and all that it
contained. More than one professional American
gentleman has spoken to us strongly upon this point.
" It was hut reasonable," says the United States
Nautical Mavazine, " to suppa,e that every facility
would be afforded Mr. Steers, now that improvement
seemed to be really intended, and, with the exception of
the propelling power in the quantity of the canvas, the
ground tackle in the kind ofanchors, and the ventilation
in the improved side lights, he has thought proper to
use, be has been allowed to exercise his own judgment,
both iu the tin lelan.l manner of construction, and is,
like the com..truesor of the Ohio, crlite wilFog to tlke the
whole measure of responsibility, havinga full knowledge
of its weight and bulk. This vessel, as her dimensions
and calculations will show, is the largest of the six, and
is also of lb very different model and construction. In
the construction of the Niagara, it is alleged that there
are principles involved which are of great importance to
the safety of vessels, which have never been appreciated
in the navy either in this country or elsewhere. It was
supposed that in the model and internal arrangements
alone would this vessel differ from the other five vessels ;
but it is discoverable that not only is the form of
the fabric and her arrangements in armament
different, but that the manner of distributing
the materials throughout the vessel is also en-
tirely different, utility being regarded as of more
consequence than the time-honoured precedents, the oon•

structor baying sought to secure the greatest amount of
strength with the least bulk."
The principal dimensions of the Niagara are as follows :
Ft. in.
328 10
345 0
55 0
53 8
51 3
26 0

Length on load-water line
Length over all
Breadth, extreme
Breadth, moulded
Depth of hold to spar deck
Draught of water ..

Her port's are 15 feet above the load-water line. Her
height between decks is 7 feet 3 inches to the under side
of beams ! Her displacement at 23 feet draught is 5,440
tons. Her frame is of live oak, filled in below with yellow
pine, and crossed on the outside with two sets of diagonal
iron plates inclined in opposite direction.. She is also
strengthened for ward by similar diagonal plates laid across
the beams of the upper deck. Her plank of bottom and
decks are of yellow pine, Having a very fine run, she
is of course weak at her quarters, in consequence of
which Mr. Steers has fitted on each side a large 2-inch
iron stay or brace, which lies along the upper deck
beams, and passing through the decks below steps upon
the stern post. This is certainly a curious arrangement
for a ship of war. It may as well be added here that
when she is docked it is thought necessary by Mr. Steers
to brace her two sides together, at about the turn of the
bilge, by means of a chain, which passes over a frame or
saddle, which is set up by wedges to tighten the chain.
She is rigged like the Merrimac and others.
The Niagara carries 12 guns, 5 of a side, and 2 pivot
guns, each of them 11 inches in the bore, and weighing
upwards of 7 tons. All the guns are mounted on pivoted
carriages, and the broadside ports have consequently to
be very large-9 feet long and 4 feet high. Through
ports of this size the guns would be easily dismounted in
close action, but the Niagara is intended to be fast, and
being furnished with long-range guns, is supposed to have
the power of annoying and injuring an enemy, while she
herself keeps out of the range of her enemy's guns. She
was, in fact, designed for the express purpose of giving
the Americans the advantage over all existing ships ; it
is satisfactory, however, for us to know that in our own
dockyards there are already several new class ships quite
competent to match her, and, if we are not mistaken, tti
give a good account of Mr. Steers's experiment. We
should be pleased to know with certainty that such a
trial of strength is not likely to came off ; we hope it
never may.
The engines of the Niagara—designed by Mr. Cope-
land, and built by Pease and Murphy, New York—are
similar to those of the Merrimac, but she has three cylin-
ders, each 72 inches diameter and three feet stroke, in-
stead of two. Each frame for cylinders is cast in one
piece ; the cylinders have slide valves, and a separate
cut-off or expansion side-valve adjustable so as to cut off
at any point from three-eighths to five-eighths of the
stroke. Each cylinder has its own separate condenser,
air-pump, and hot well ; in fact, there are three com-
plete engines, so that, should either become deranged,
the others would be still available. The screw propeller
(formed of composition) is 18 feet 3 inches diameter, and
4 feet 2 inches long, with pitch of 29i1 feet (at the peri-
phery.) The boilers are four in number, 11.12- feet long, 21
feet wide, and 15 feet high. Like those of the frigate,
they are Mr. Martin's vertical tubular. They are set in
pairs, the flues discharging into two chimneys.—Mcchcc-
nics' Magazine.