Daily union and American. [volume] (Nashville, Tenn.) 1865-1866, 1866-09-25
IRON PLATES---ARMOR FORTIFICA-
TIONS-EXPERIMENT SATFORTRESS
MONROE.

FORTRESS MONROE, Sept 24.-After in
Vulnerable delays the ordinance experiments
commenced this morning by the board Of en-
gineer officers appointed to investigate the
value Of iron for pertinent Qualifications.
The guns which were used were well tested
previously, and consisted of fifteen inch
smooth bore Rodmans GuTl, and twelve inch
rifed piece Of the same patent. iay
At half past eleven the first shot was fired
from the fifteen-inch gun at a wooden target
placed at the right of a stone one, so as to
obtain proper elevation, and few moments
later the firing commenced. The following
is correct list of shots and their effect upon
the target as made from personal observa-
ton.
The first shot was fired from a fteen-inch
Rodman gun, at an elevation of forty min
utes, charged with forty-six pounds of
POWDER weight Of ball, round shot, 432
pounds. Its effect was an indentation in the
plates about fifteen inches in diameter and
three inches deep. At the rear of the target
two granite blocks were broken and forced
outward, and the seams opened in their i'm
mediate vicinity. The pressure on the guns
was IL 900 pounds, and the velocity Of the
shot !, l55 feet
The second shot was fired from the tame
gun with still less elevation, the change Of
powder and weight of the ball being the
same. The initial velocity of the ball was
1,l30 feet per second, and struck the hiwer
plate one foot from the ground. The inlen-
tation reached 81 inches deep, and Is inches
in diameter, the plate in this instance, hav-
ing a backing of six inches of sand, while
the upper one rested directly against the
face of the target The damage TO the ma
sonry, however, was found to be considerably
less. Three of the blocks at the back of the
target we're merely started from their posi-
ton and none broken.
Third. Shot was fired by the u inch Rod
man gun; Dyer's spherical projectile was
used, with charge Of So pounds of powder,
and n half degree elevation given to the
piece. The initial velocity of this rife
shot was less than the Is inch, being only
1912 feet a second. The upper plate was
struck, making an indention IA inches in
diameter and AZ inches deep. Two blocks
of granite were broken on the back of the
target, and the seams between other blocks
were opened.
The fnnrth shot was fired by the san,o
gun, charge of powder, projectile, and ele-
walton. The initial velocity of the shot was
1919 feet a second, producing an indenture
Is inches in diameter and 81 deep. The
masonry on the back Of the target was con-
siderably damaged, and the blocks broken
by the previous shots crumbled into numer-
Gus pieces.
The fifth shot was fired by the same gun
and charge of powder, etc The elevation
of the muzzle being considerably less, the
projectile, with an initial velocity of 1,103
feet, struck the lower plate about three feet
from the ground This shot was conceded
to be the most damaging of the five, and
played sad havoc amongst the granite in the
rear. An indentation was produced fourteen
inches in diameter and seven inches deep,
splitting the iron plate into innumerable
crevices and nearly penetrating to the sand. |
The experiment terminated for the day |
with these results, and will be resumed to- !
morrow and prosecuted until the entire tar |
get is a mass of ruins. The effect Of the |
shot fired at the target, which is six feet |
thick of solid masonry, carefully put to- |
gether with iron domets and taggets, and |
iron-clad with four inches Of rolled plates, |
was tremendous, and ELECTED the astonish- |
ment and admiration of all the officers con-
Quoting the experiments.
The opinion was strengthened, although |
generally at variance with the views enter |
iained beforehand, that the sixinches of sand |
adopted as backing for one of the iron
plates, would not answer the object Of the
and that the greatest resistance
was offered where the plate was next to the
lace of granite.
A similar number of shots will complete
y wreck the stone work of the target, but
rot materially damage the iron plates, be-
Iond the indentations, which have not as
yet been penetrated save in the instance of
me lower plate, and its sand backing. The
fleet of the shots is transmitted from the
ron directly to the masonry, and is made
'isible in the crumbling OF the blocks in the
ear Of the target al