The Sun.
London, England, 1862-04-26 00:00:00

IRON SHIPS AND FIXED PORTS.

Sir S. Morton Peto, M.P., has addressed the fol•
Lowing letter to one of his constituents on this im•

portant subject
" My dear Sir, I am greatly gratified by assur-
ances of the approval of my constituents of the course
I have pursued on the fortification question.
" The unanimous adoption by the House of Com-
mons, on the 4th April, of the resolution proposed
by Mr, Osborne, and seconded by myself, ' That it
is expedient to suspend the construction of the pro•
posed forts at Spithead until the ;value of iron-

roofed gunboats for the defence of our ports and
roadsteads shall have been fully considered,' was,
no doubt, a step towards a better system. I trust
that Parliament will steadily persist in the policy
thus initiated. On no consideration ought any ex-
penditure to be sanctioned on works which are, in
every sense, so completely indefensible.
" I cannot, however, but express an apprehension
that it is intended, after Easter, to make some pro-
posal to Parliament which will have the practical
effect of reversing its decision. The gunnery expe-
riments at Shoeburyness, the speeches of Lord de
Grey and Ripon and of the Duke of Somerset at
the last sitting of the House of Lords, the recent
inspections of the sand banks at Spithead, and
above all, Sir G. C. Lewis's official reference of the
whole question back to the Defence Commissioners
for their reconsideration and report—all indicate
that some attpmnt will b made to induce the House
dl uommons to vote further sums of ",
tional defences in the form of fortifications. Allow
me, then, to state to you why I shall most certainly
continue to oppose, with the utmost determination,
any motion involving such expenditure.
"I. Properly understood, the experiments with
Sir William Armstrong's great gun at Shoebury-
ness afford additional arguments against fixed for-
tifications. Those experiments prove that a gun
may be manufactured of sufficient strength to carry
a charge of even 501bs of gunpowder—a charge
which will propel a projectile with enough force to
pierce almost any rigid plate within moderate dis-
tance. No doubt, means will be found to adapt
such guns to floating batteries ; and there is no
question that from such floating batteries any fixed
objects can be struck with almost unerring preci-
sion. What the experiments really show, therefore,
is that fixed forts must be of vest strength indeed
to withstand the battery of such ordnance from a
floating, movable, or other platform.
"But these experiments, you will observe, do not
touch the case which is the converse of that posi-
tion ; or, I might rather say, they prove that con-
verse. For, by showing the penetrability of a fixed
fort, they establish the superior advantage of a
moving fort. Whilst it is easy enough to strike a
fixed fort, every artilleryman knows the difficulty
of striking a moving object. In the case of a mov-
ing object the gunner at a fixed fort has to allow—
first, for the time occupied by the projectile in its
passage through the air ; second, for the motion of
the. object to be struck ; third, for the alteration of
his elevation to meet the variable increase of range.
Experience shows that to strike a vessel in motion,

at any distance, by a shot from a fixed fort, amounts
therefore, practically, to an accident. Capt. Sulli-
van, R,N., one of our most experienced naval offi-
cers, told the Defence Commissioners, in his evidence,
that he had never heard of any one instance of a
ship being sunk by a fort, either when attacking or
running past.' Capt. Sherrard Osborne, C. 8,, of
H.M.S. Donegal, has declared that ' the Donegal,
under steam, drawing 27 feet water, shall rattle
about the waters at Spithead, at eight knots an
hour, hit the forts every time with her 100-pound-
ers, and not one of its 200 shots shall hit her. All
the engineers in all the forts,' he adds, 'shall fail
to give her range or position for more than a minute
at a time ; for her change in position would be thus:
—8 knots equal to 2,000 yards, multiplied by 8,
equal to 16,000 yards per .60 minutes, or 266 yards
per minute, or one eighth of a mile geographical.'

So sensible, indeed, were the Defence Commis-
sioners of the importance of the evidence on this
head, that they themselves reported Vessels
would offer so small a mark at a distance that
even the accuracy of the newly-invented rifled
ordnance could not be depended on for striking them;
and when it is considered that each will be in mo-
tion, and that it will be impossible to estimate
correctly their distance, thus constantly varying, it
may fairly be assumed that they will incur but little
risk in such an attack. When great stress, there-
fore, is laid on great guns, we must bear in mind
that the value of great guns depends much upon the
use which can be made of them; and that even the
Defence Commissioners agree that great guns in
fixed forts are of no avail against ships in motion.
" 11. Another important point to be considered is,
that these forts would be absolutely useless either
as a defence of the coast of England from invasion
by an army, or of Portsmouth Harbour from the
entrance of steamships iron-clad. An invading
army would seek to land out of reach of any forts ;
but inasmuch as that army must be brought to our
shores in vessels which a steam ram could run down,
it follows that iron vessels carrying shielded guns,
propelled by steam power and acting as rams, might
easily destroy the fleet of transports which con-
veyed an enemy. Such iron rams might also en-
counter with success any vessels of their own cha-
racter and class which might approach our shores,
or try to force their way into Portsmouth Harbour ;
but on the other hand, it is recorded, on the best
authority, by the Defence Commissioners, that ' No
forts of any size or description could prevent the
passage of iron-plated ships through a clear chan-
nel ;' and therefore those commissioners formally
reported We arc
convinced that no practicable
mbatteries can be depended upon
taosotuonpt of fire from
the passage of steamships, if the channel is
sufficiently clear to allow of their proceeding at