, 1863-11-07

One = +IIeAI.,s
We have already noticed the fac! that pre-.
partitions were progressing At the Fo7t Pitt
Works. In this city for ths mannfac ura Of
twenty inch guns, the lathe, patterns, &c j,
being in an advanced condition. As thu et.
pertinent, of manufacturing gun Of such 4
cslihre, however, is ore Of great risk, it WIS
det. rmined tosettle at least one point practt-
cally before tfyirg to mould the great gun,
BY melting: ut single heat, nearly the same
quantity Of metal as would be required for
the twentJ-fnch. For this purpose t7o guns
were moulded Of The ffteen-ioch navy pat
tern. and each ia. nfshed with a. twelve fnch,
1tstcad Of a fieen inch, hollow core, making
the rough weight Of each of the guns nearly
a great as that Of the columhiad fifteen. Inch.
These moulds were placed aide by side In tue
pits Of the new foundry, and on Saturday
lnonirg five Of the furnaces in tbs fouadFy
were charged, three for the special purpose
Of eating the great guns, and two for the Or
dtnary work Of the shop. The respective
weights Of these charges will give some idea
OF the capacity Of these enormous furnaces,
4 being tbifty-f9ar, pine.een, nineteen. toi:fsen
md eight and half t1ns, M aggregate of
nearly ninety.four tunr, and far greater
amount Of metal, we believe, than vas ever
reduced in furnace in single establishmeot
iu one day Seventy-tFo tans OF this met,l
Icing the charge If the three large furnaces,
we're designed for the casting Of the expert
mental guns. The metal was led from each
from each Of the moulds, and communicating
by two "runners" with the two "gates" Of
each.
About one o'clock the three furnaces we're
tapped in quick succession, and iua moment
three streams Of molten iron we're pouring
to the level Of the openipge, two fiery lines
sAot into each Of the moufds. The Intense
heat Of the iron, pouring oloug these seven
streams, with the molten mass in the reser-
yolr. seemed to have no extraordinary effect
on the worknen, who performed their accus-
toned duties Of skimming and clearing tue
1houlds with as. much indifference as # tho
glowing metal surrounding them, aud filing
The air with showers Of sparks, were harm
less as streams OF water. Familiarity With
such situations is apt to breed contempt Of
danger. but We believe that no accident has
ever yet occurred at the works during the
pnutuslly. risky character Of the experiment
on Saturday, everything. passed OF success-
1ul1y, and the streams Of hot metal and cold
rater, crossing and inter1aciDg on their way,
pc1hed Ere ai,sd 1sto the moulds without accident
demonstrates the capacity Of the works for
The manufacture Of guns Of 20 inch caliber,
The furnaces, charged with seyenty-two tuns
Of meta! On Saturday, have An aggregate ca
Eaclty OF over ninety tuns, and can supply
that amount Of metal, If required. for sins&
castlpg. We hayo seen no reliable statement
OF the weight Of. the projected gun, but pre-
snme that Its rough draft In the pit, viii be
e1resn seventy and eighty tons. The rough
Weight OF the 15-Inch cplumbiad is about
tht1ty-seyen tons, and the new gun will be
nearly twice rs heavy. No other establish
ment IN the country has 4 present capacity
for casting Of such magnitude, and we PEE
EuTne fhEra are rnna nf n ff1nInnt naY,, .,e
tue other side Of the At1aatic.-hNs5urgh
DiD0{ch.