The evening telegraph. [volume] (Philadelphia [Pa.]) 1864-1918, 1868-07-08
1hO n FORTS.
ENnArNr
G1psF .Asntu at shoeburynsss.

como >ndOn Times reports the res ult of
onri important trials of iron structures
o lIoable to land Notifications. They had
.&oited great interest, and the attendance at
ShoebuTyness was very large. The structures
to be fired at were erected about 100 yards
within the low embankment protecting the
ground from the Thames the front OF the
works facing inland The Plymouth target
and the other casemates were in the centre,
fanked on either hand by the experimental
walls and plates.
The appearance of the larger structures was
massive and imposing, bat their effect was
somewhat marred by the large black surfaces
OF iron wall being divided off into squares by
white painted lines. The details OF cOnstruc-
ton were to a considerable extent hidden by
the close fitting OF the external parts; but
ample information was supplied on this point
by the exhibition of autographed plaus aud
sections OF the structures, showing all their
parts in full detail. Red and blue lines were
aleo painted on the targets to indicate the
places OF the joints and other important fea-
lures in the construction, and printed descrip-
tiOns prepared iOr the purpose, were circu-
lated among the visitors. Diagrams were also
exhibited, showing the various data Of the
artillery, and a notice Of the gun, charge, and
prOeCtie was posted up before each round.
The chief object was the Plymouth shield,
and the only gun used, with the exception of
two rounds from the American Rodman, was
the largest ritled gun, viz, the twenty-three
ton gun, of twelve inches bore, carrying a
Palliser pointed shot Of 600 pOdnds. The
charges were originally intended to be such as
would represent the effects at distances of 500
and 1000 yards; but as it was considered de-
sirsble to test the strength of the shield with
the full power OF the guns, the battering
charge OF seventy-siX pounds of powder was
used every round.
There were in all eight rounds fred against
the shield, five of which were directed against
the part to the right of the portfolio, strength
ened by an extra fve-inch plate in front,
giving in this place twenty inches thickness of
iron. The other three were fired at the thin
ner or ffteen-iuch side OF the shield
The first shot hit the live-inch strengthening
plate about three feet from the ground and
fifteen inches from the right hand edge, tear
ing open the narrow strip outside the shot.
One bolt was driven several inches inwards
and the inside plates and the vertical standard
behind them were slightly bulged. The shot
penetrated about a foot aud broke up.
The second round was a she'll OF the same
weight from the same gun, with bursting
charge OF l45lb. This struck about six inches
above the port, and exactly on the left edge of
the strengthening plate, so that half the pro
jectile acted on this plate and the other part
On the thinner part adjoining. In front no
damage was SEEN but at the back it was found
portfolio was broken in two on the right hand
side of the port and partly thrust backwards.
The bolts near the part struck were strained,
bnt not broken. The shell did not bury itself
deep enough i'll the iron to do more mischief
than shot, as the bursting charge exploded
in the rear.
The third round was a shot from the great
American 'Rudman" gun, with a lj-lnch
BORE and cast-iron round shot Of 45O pounds
weight. The usual charge in America for this
gun Is 90 pounds, but, as it is said to be some-
times used with 100 pounds, it was deter
mined to try it with its full power, and for
that purpose it was loaded with S34 pounds of
our powder, which tIom its great strength is
found equivalent to 100 pounds American.
The shot struck the strengthening plate about
Is inches nom the bottom, aud little to the
right Of the middle not far from the shot of
the first round, 1t cracked the front plate,
started another bolt, aud bent the inside layer
of iron, doing altogether, but little damage.
The Shot rebOunded, and fell, much hatteu9d,
a few feet in front OF the target. 1t was of
American make, and appeared to be of excel
lent iron.
As the last shot was said to have grazed the
ground before arriving at the target, and
thereby to have lost some of its force a second
shot was hGed from the same gun, also AZ this
strengthening plate, WEIGH it struck five feet
high and one foot six inches from the left haad
edge. IL made an ludent OF eight or niue
inches, cracking the plate through to the edge,
and knocking oil by the shock from the right
hand corner piece OF plate already brOlsu
by former rounds. The inner plauks near
the port hole were distorted, and an upright
standard slightly bent. The shot struck on a
spot where the plates were supported by QUE
of these standards, aud which was, therefore,
a strong place; but the effect of both these
rounds appeared so small Tor the large charge
of powder as to give but an Indifferent opinion
of the power Of this bOasted American weapon
compared with our own rihsd guns,
For the fifth round the l2-inoh riaad gun
was resumed, and another shot was fired also
at the thickening plate. IL struck about six
feet high, and near the middle OF the plate
IL penetrated thirteen inches and broke bolt,
doing also considerable damage behind. It
pushed out the middle layer OF iron, aud broke
one of the horizontal pank5 of the internal
layer, piece of which, weighing between two
hundred pounds and three hundred pounds
was violently projected about One hundred
feet to the rear OF the target.
The three remaiuing rounds were aimed at
the thinner part of the target, representing
what is actually in construction for the forts,
and fifteen inches thick. lt was intended that
at least one OF these should hit part between
the upright Standard, where the plates were
unbacked; but this was not accomplished,
each Shot striking place Immediately in
front of the upright standards The sixth
round was a solid shot, which penetrated
about ten inches, broke two bolts and caused
bulge in both the back plates and the stand
ards. The seventh round was a shell, which,
like all the others, burst outside, and did little
further mischief; and the eighth round was a
solid shot, that caused a large bulge in the