The national Republican., 1867-01-17
HEAVY ORDNANCE.
Letter from Mr.. wizard.


wAsmseroS, January 10, 1857.
EprroR RxPuBLroAs I hsve just returned
to washington-after an ahsence of few
weeks-and have seen copy Of your paper
containing my reply to the critieism Of zone
ofthe Smith family" in print. While l re-
gret that my rejoinder was written hastily,
and that, consequently, did not write the
best hrgument that would have occurred 10
me after a few minutes consideration-for
instance, regret I did not say, after quoting
the paragraphs from my friends letter, II
know Of Rodman gun which has ,withstood
1000 rounds, and still apparently in good
condition"-(referring, Of course, to 80.
pounder) sand maybe seen on the grounds
Of the Washington arsenal.
The gun. was fred continuously from
morning to night, but it did not burst from
unequal expansion" " . "Guns have
been made ofwood, leather ,cast.iron, wrought.
iron, csst.steei, and wroughtstesli all have
burst In turn, leaving fhe matter still an e1.
periment." Guns have been
made Of ice in Russia and fred several
times without bursting" and "Lord Elder
recently stated in England that none Of
Armstrong; guns withstood, over 400 rounds,
and most Of them burst under 300 rounds;
and quite recently we hear that the Knnpps'
caststeel guns have also proved . failure
Even the unburstable guns Of Mr.. Ames
tpiH burst; one even bursting not long ago
while proving as understand, from some
defect In the manufacture; and where is
| A -. 4 IL ,.h,ah "a mn
\ sterling Why Il burst on the fourth
\ round. Are these results Of unequal dis
| tribution OF heatH" That his examples showed
| a remarkable uncertainty attending The en-
| durance of guns, and, to certain extent,
was quite as good an argument as ! could
use 70 establish my theory, which in fact
was first suggested to me by just such ex-
amples. -rLr-rras -l,...F...
noticed as early as 1861 that the strong.
est gun did not have the quality OF endur-
ance, 1. c. gun made OF steel large size)
with tensile strength Of 10000 pounds to
the square inch Of section, would burst
quicker than gun Of the same model and
size made Of castiron, even although after
bursting the fracture should show that the
,pelds and honogeniety Of the metal pas
more perfect in the steel gun than in the
cast-iron. An examination or Rodmdn's
book will Disclose that the Deakest gun of
pairs, made Of the same model, size, and in
the same manner, would endure q greater
number Of rounds than the strongest. Now,
I would ask, to what other cause can this ano-
maly be attributed than the unequal expan-
sion Of the gun when fred rapidly, Il ii
be Of such thickness as not TO heat through
the wallsH II IL be the fact that cubic
inch Of iron heated to ls0 degrees expands
with a force equal to lifting seven tons az
| tons in my letter Of the 18th was an error)
one foot high, or equal to lifting 1,344 tons
onesixteenth Of an inch high, sufficient land
more) to cause rupture on q 15inch gun
without any other pressure whatever.
What other unequal or ununiform effect is
there to the force Of powder when ignited
Does not the same charge project the shot
or bullet uniform ranger II Il does, then
the pressure Of the powder 10 uniform. Has
The metal Of the gun Q uniform strength
when subjected to the test Of pulling II apart
by weightsf Undoubtedly; or II not, why
strength in testing maehinesf
Why does the 6S-pounder English gun
exhibit greater endurance than an Arm.
strong, with the same charges, when fred
rapidly2 The English 68-pounder is made
Of iron, Of 10000 lbs. tensile strength, while
| the Armstrong would endure at least twenty
times the pressure in the interior.
hoped TO have been enabled To read the
next Communication Of your correspondent
Smith" by this time with the "better theory"
promised. When any man attacks me, i'm.
putting improper motives TO me in my trans
actions with the Government, or charges
that am in the habit Of advancing erro-
neous theories on any practical or scientific
question, publicly, no matter how triHing the
interest involved, through the press, I will
either set him right or be convinced myself
and acknowledge my error as publicly.
have for the last Eve years continued to
state through the public press that Gen.
Rodman was producing guns on erroneous
plans, either through ignorance OF the prin.
ciples involved or through the sel6shness Of
himself or Of his associates in the manufac.
ture Of heavy ordnance. challenge him
or any other person advocating his theories
to reply to the statements make as pub.
licly, that the people who pay the cost Of
his errors may judge wto is right. Does he
ignore public opinion altogether .