Year: 1864

CAST AND WROUGHT IRON GUNs.-One


of the questions of greatest moment In war


lust now is whether the large cast iron


guns may or may not be considered sue


cess. A recent number of the English


Quarterly says: 1--WE happily know what


the Americans have done, or rather what
they have failed to do, with their artilley,
and we may entertain the comfortable as
surance that the superiority claimed for
the Americans in this matter is-as ground
less as their boasted superiority over US IN
many other respects" There Is no ques-
ton that we have succeeded in casting
the largest guns that ever were made. Re-
Gently twenty-inch gun has been sue
cessfully cast, fifteen inches being the lar
eest size before attained. The first diff
Guilty has thus far been in manufacturing
cannon of such size at all Unless they
are made at one time the repeated heat
ings, as in the case of wrought iron, must
render the strength unequal. On this ac-
count, among others, cast iron guns have
been thought by Americans to be best.
The Quarterly laughs at our monster cast
iron guns, calls them "treacherous


weapon, and hopes England will never
use any but those Of wrought iron. We
only hope they will stick to that opinion.
For we can cast at least twenty cast iron
guns while they are forming one OF
wrought iron. Thus far, anything like
twenty inches has not been attempted
there. AS to their want of safety, under


proper conditions, our cast iron guns have
thrown shot without bursting further than
any shot fred from any other weapons.
No doubt if they were cast as thin as
wrought iron guns they would be unsafe;
but we can afford to make them Of any
necessary thickness, and yet handle and
elevate them better on board ship than
English guns are handled, and with fewer
men. It would, no doubt be impossible
to cast such guns without great skill and
care, but at Pittsburg that care is used. Of
course, the great trouble is that iron
shrinks as it cools. If the guns were cast
solid, the outside must cool first, and the
result would be that the outside would
split open from end to end. But by cast
ing them according to Colonel Rodman's
plan, hollow in the middle, that is, with q
core into which pipes are introduced.
through which water passes, by regulating
the temperature of that water and Of the
atmosphere in which the gun is allowed
to cool, both the outside and the inside
cooling processes can be regulated 50 that,
Notwithstanding the extraordinary thick
ness of metal required, but few compare
tive failures take place. A large portion
of the outside iron is, no doubt, honey
coined and unreliable, because OF the
shrinking. But this is turned OF, and the
inside is solid in proportion. so, also,
these cannon have to be cast two or three
feet longer than they are intended hnaly
to be, because the guns are cast perpen-
dicularly, and the upper part is found to
be weaker than the lower portions Of the
casting, and is therefore cut of. The core,
too, is considerably smaller than the bore
is to be, so that the lathe has to pare away,
outside and in, nearly half the gross amount
of the casting. But that done, and nice
care being taken as to the quality of the
metal employed, degree Of hardness and
toughness united Is attained, and it is yet
doubted If wrought iron can compete with
it. No doubt wrought iron may be made
more tough for enduring strain. but it is
seriously doubted whether its softness will
endure the action Of the bali upon its bore
so well, or can be made to do 90. The
English boast that our guns can only be
fred with such much slower initial veloc-
ity that it will be of no use for US to at
tempt to compete in point of effect with
their finer powder and more sudden ex-
plosions. This remains to be proved.
We have sent our shot the furthest, and it
yet remains to be seen whether our larger
shot will not produce greater smashing
effect on the sides Of a ship than the more
swift but smaller shot Of the English. Il
is, however, the cheapness Of the cast iron
over the wrought guns which must make
them more commonly used. .-Lsdor.