The Sun.
London, England, 1864-08-06 00:00:00

Important Experiments at Shoeburyness,

Oa Thursday last the Iron-plate Committee
brought their official existence to a close with some
experiments upon a target representing an ironclad
built to scale upon the principle generally adopted
on the Continent, and more especially by our
neighbours the French. Nearly all the Iron-plate
Committee were present on this occasion, together
with a large number of ofacors of both branches of
the service, who were specially interested in seeing
how the theory of foreign armour ships would stand
the downright practice of such heavy ordnance as
Shoebury could bring against them.
This target, the trial of which closes the labours
of the Iron Armour-plate Committee, had been
made at the suggestion, and according to the draw-
ings of one of its members, Professor William Pole,
F.R.S. Its object differs somewhat from that of
most targets hitherto tried; for, whereas the usual
endeavour has been to test novel constructions
offering promise of increased resistance, this experi-
ment only proposes to obtain exact information as
to the actual strength of a very simple and compa-
ratively slight structure, but still one largely
adopted in practice—namely, a wooden ship with a
plain armour-plate covering, and without any extra
strengthening devices of longitudinal stringers, &c.,
such as those lately tried in the Lord Warden and
others. At the same time, to render the experi-
ment as useful as possible, Mr Pole has taken ad-
vantage of it to try the value of some inventions,
which, though approved by other nations, and
especially by France, have not hitherto been fully
tested in this country. These are—the use of plates
of small area, and a peculiar mode of fastening them
to the ship with large " wood screws," holding by
coarse threads in the timber, instead of bolts pass-
ing entirely through, with nuts on the inside, which
is the usual English plan—and a most defective

one it is.
The target represented a portion of a ship's side,
lift. long and 10ft. high, covered with four rows
of plates, each plate being about sft. 9in. long and
2ft. 6in. wide, The two upper rows were 4tin.
thick, the two lower nearly 6in.—that is to say,
5 15.16 in. Each plate was screwed to the ship
by about 15 screws, each in diameter, and
penetrating well into the ship's timbers to the
depth of 16 inches. The hull was composed of verti-
cal frame timbers of oak, 11 inches thick ; outside
planking' of teak, 10 inches; and inner planking of
oak, again, 6 inches, all strongly fastened together.
Behind this were portions of decks and deck beams,
strengthened in the manner usual with French ar-
mour ships. These strengthenings consisted of mas-
sive oak brackets, which filled up the angle be•
tween the ship's side and the deck, and occurred at
intervals of about 3ft. apart, answering much the
same purpose as the iron beams used in our own
men-of-war. These, however, appeared to be
stronger ; were certainly placed closer together, and
were, besides their own strong 2in iron bolts, six
in number, still further secured is the deck and the
side by broad, powerful, wrought iron brackets,
bolted through on each side. Every part of the
target, in fact, was contructed on the principle
universally in use on the Continent, and, above all,
in France. The whole target, that is to say, its
6in. plates on the waterline, and plates
above—may be said to have represented the last and
best of the French ironclads—the Flandres; while
the upper half—that is, the 41. n. plates alone—
were in most particulars a general copy of La
Gloire, the wood backing being similar in both
La Gioire and the Flandres. How 6ia. and 41-in.
plates will stand under fire of heavy guns was, of
course, as well known before the experiment com-
menced as at its close. The trial, therefore, was
simply undertaken to test the continental system of
small plates fastened with a large number of screws
instead of bolts. These screws were supplied direct
from France, and were used so numerously about the
plates that at no part could a shot strike without
having its circumference within two inches of no
less than four of them. As either screw or bolt holes
in the plates are evils and recognised sources of
weakness, it was believed that the plates would
soon yield under fire and crack in all directions ; but
the absolutely perfect manufacture of the iron made
by the ?rlillwall Company disappointed this expec-
tation, for, though the target was penetrated and
destroyed more absolutely than any target that has
ever yet been tried at Shoebury, not a single crack
was visible in the iron from first to last. More per-
fect plates have never been experimented on, and a
most apt illustration was afforded by them during
the course of the day of the value of the long labours
of the Iron-plate Committee, which were on Thurs-
day brought to a close with this trial. The target
was fixed right in front of the once-famous Scott
Russell target, tried about three years ago, and
built of plates which were then thought marvels of
manufacturing e-..cellence, but which, nevertheless,
cracked like glass under the shot. On Thursday
almost every shot went clear through the French
target, and afterwards struck full with more or
less of force on Scott Russell's. When they did strike
the latter hard they generally cracked a plate, but,
as we have said, the plates in the French
target never gave a sign of weakness, though it
was perforated in all directions, and once with a
shot so close to the circular hole made by another
previously as to leave only a narrow but a perfect
strip of iron like a lattice bar between the two. Even
from the plates of John Brown and Co. finer results
have never been obtained, and we are not say-
ing too much in praise of the Iron-plate
Committee in attributing to their patient and
careful investigations and the results of their
valuable experiments much of the high superiority
which our own plate manufacture now enjoys
throughout the world. When the committee began
their labours, about four years ago it was an almost
unknown circumstance to get a shot through any
target, but it was then almost equally a matter of
course that the plates shattered and cracked in all
directions under the fire of the least effective guns.
In the interval that hes elapsed both the Ordnance
Select Committee and the iron- plate Committee
have been steadily at work, the former perfecting
our means of attack in guns, the latter improving
our system of defence in armour plates, and, as was
to be cxpeoted, the former have gained the advan-
tage. True it is that our armour-plates have been
brought to each perfection that a crack in a plate,
even under the raest incessant firing, is rarely seen;
but, on the other hand, what with larger gua3 and
,L'ael shot it is now taken as a matter of course that

our heavy ordnance can as easily pierce any system
of a:mour-plating that can reasonably be expected
to am: at sea as if it was so much wood. In plain

telmae, this is really the result et which all the Shoe-
buryneas expetimenta have at last arrived. No

matt,n• what this ;srget or the system of coating,
wheth et it ht.' Cnalmets'a or the French plan, 6-inch

plates, a cupola or one of the Wdrriors or