The national Republican., 1867-01-02
The Rodman Guns.
FoRrRnss MosRo.. Deo.mb,

fohrhnss MONROE Deosmber "a, 1900.
Editor of the NATIONAL R,pubiiean:
Sin have just REID letter in your pa
per Of the 18th inst on the Bursting Of
Heavy Ordnance" by Norman Wizard, Esq,
in which he makes some vary singular
statements.
He says that "a Rodman gun consists, Of
q series Of layers" and likens its constrUG|
ton 10 "a tallop candle or an Armstron.
gun"
The Rodman gun is cast hollow; while ID
the molten state the bore is chilled with !
running stream Of cold water. The cbillink
process is very gradual, but continuous; the
casting, therefore, becomes one homoge-
neous mass, The only chance Of layers
forming in the process Is on the surface, in
ternal and external, which Is peculiar to oil
castings, and are SO thin that the necessary
process Of finishing feHorss-t hen. F.
II may be that the interior of the
is more dense than the exterior, by red
Of the contraction Of the outward mass; bu
the word layer has no relation TO It.
would rather liken it to hill Of homoRd
neous sand; the bottom being more com,
pressed than the top, but the weight is so
gradual that at no point ia there layer.
Indeed, were the Rodman gun in layers. II
might be an advantage, for O crack at The
vent would be confined TO the first layd,
The crack would return to place itself TN
Rodman guns when burst exhibit no laya.
Mr. Wizard further says: again, whenIs
gun is fired heat is communicated TO the sur
face Of the bore, and II can be seen thatLf
the gun has been constructed in such man
ner as to best resist the pressure Of tle
powder, 1t will be burst by the uneqaal ehl
pansion from the heat communicated. III
this theory were true, every Rodman guA
would be burst after few rounds of CO..
tinuous firing, which is not the case.n..
know OF Rodman gun which has with.
stood four thousand rounds, and have seen
q Parrott 200-pounder, the casting made On
the Rodman principle, burst on the third
round, after proof have seen a 200-
FOUNDER Rodman burst on the fiftieth rourii,
and 1 have seen one burst on the fifteen huln.
dredth round. .n T
have been present at the continuous Ar.
ing Of Rodman $50 which withstood Ak.
teen hundred rounds and still apparentlyIn
good condition, and may be seen on Inc
grounds Of the Washington Arsenal. The
gun was fred continuously from morning
till night, when it got so hot that Il was
deemed unsafe to fire il. II was cooled with
snow, yet It did not burst from the unequal
expansion. ....
Mr.. Wizard says that no Rodman gun will
withstand twenty rounds fred in quick sue.
cession. l have seen Rodman gun fred
over one hundred times in quick succession,
and it did not burst
Numbers Of large Rodman guns" says
Mr.. Wizard, "haye been made, and are being
made and mounted. They are on dress
parade, principally on forts that have never
been attacked, consequently that class OF
guns have never been subjected to the real
test OF battle. How sad II will be il we never
learn their utter unreliability until the emer-
gency arrives for which they have been pre-
pared"
This is bold and easy style Of writing,
and wholly unsupported by facts. Guns
have been made OF ice in Russia and fred
several times without bursting, at the celel
bratlon of GATHERINGS marriage. Guns have
also been made Of wood, leather, cast-iron,
wrought iron, caststeel, and wrought steel,
all have burst in turn, leaving the matter
still an experiment.
Lord Elcho recently stated in England that
none Of Armstrong; guns withstood over 400
rounds, and most Of them burst under 400
rounds. And quite recently we hear that the
Krupps caststeel guns have also proved a
failure. Even the unburStable guns of Mr..
Ames DiH burst; one even bursting not long
ago, while proving" as understand, from
some defect in manufacture; and where Ia
Armstrong; celebrated big Will," which
cost 1000 pounds sterlingH Why it burst
on the 4th round. Are these examples the
result of the unequal distribution Of beatY |
think not, since guns Of every grade and
make sometimes burst from causes not we'll
understood.
deem 1t reasonable to suppose that the
premature bursting Of guns has its origin in
q cause that is not uniform. Heat is uni.
form, and were Mr.. Wards theory true, all
guns would burst after few rounds.
In my next shall endeavor to give bet
ter theory to your readers than that of Mr..
WARDS relating to the bursting of heavy ord.
nance; hoping, meantime, that Mr.. Wizard
will yet have more faith in the genius of his
countrymen. Very respectfully,