The New York herald., 1867-01-31

inches between itself ana The pattern This space
then filed with the moulding sand which 10 ramDe0
every part Of 10 interior surface Ths pattern, bs re-
membersd, Is simply the gun in wood, being in size.
when lifted nom ihs pit when the mould has been
finished and has remained sufficiently long receive The
Impression Of the pattern thoroughly IN every part -
them sssi.nsy hard 1s % become rsosps.ess isr
70 bs made Then they are boitsd ana passsd together
ey preparation Of cement and lowered into pit con-
on the inside. and has crate bars Il The bottom,
which nre can be built Iron dues On each side o. i
reaching 70 and nush with the surface Of me you5s.
IRE TO burn well when lighted Fuel 10 then put on the
crate bars What 10 termed the "core barel' s then
introduced Into the mould that perpendiCu
ary in the pit lin which position the gun always cass
This core barrel 10 hollow tubing presenting the ~
put into the pit wrapped around evenly with hempen
cord and covered with pase II forms the Of the
S abused ns centre Of ee mould nss q
this is now placed small hydrant pipe which extends
70 within one inch Of the bottom Of the barrel through
this pipe cold water is introduced which, ravereng the
inch o. space At the bottom rises gradually and ns The
barrel whence is led on By surface pipe Tne uss II
IRON Of which the gun Is 70 be made II sssshing in the
melting furnace From this furnace 70 the casting ps
osns ssass sSnss arc Ss furnace sn0
when away goes the molten lava.like maternal,
following the course Of the runners into the mould,
standing perpendicularly in tho pit The mould being
nlled the furnace zap closed and tho influx Of
stopped The fuel which had been previously placed
BY dropping into some molten iron, a and the Di. s snsa
entirely covered with ssgments or sheet IRON The
drant tube and circulating inside
barrel until II reaches the surface when il 10 led on by
cool the inside of the gun FIRST while the fire above ne
crate bars keeps the outer portion Of IL still heated.
ordnance Tor which General i. J. Rodmap oSssinsd
. patent and ordnance cooled in this manner ere
known e !" Rodmsn guns That portion Of the iron
piece, and BY the Introduction and crcuation
Of water on the Rodman principle the inside Of ths
ordnance Is soidfed and made much stronger than the
outer surface Formerly, when by natural action the
guns cooled from the outer surface inward the spongy
invariably the inside, and close contact with
the propellng power; but BY the Rodman system The
su. S s % inner
fact obvating them entirely The cooling process gsn
Of ten inch calbre occupies about i've days. while that
Whenever the water comes up TO the surface drain Of
temperature exactly equal to that possessed entering
the core barrel the gun s known % BE- sufficiently cooled
An immense crane, near which the casing pit 10
always dug, Is then brought into reQuistion 70 effect
this removal: This huge pieos Of mechanism has an
arm Of Brobdgnagian proportions outstretched over
sSsn! % These are % firmly al .s.aonsS e the pscs
10 the pit, and the power Of tho steam engine
which sets the crane in motion is applied. when up
comes the monstrous cannon, apparently az easily ~
fond mother would lft her infant from the cradle
strongly built platform car stands ready to receive the
is safely deposited and taken 70 massive lathe in she
boring department.. where IL is bored and
the pit, tho outside Of the psee is rough
and bark-like In appearance. and y = placed 10
process performed BY the use Of turnng tools come
what after the manner Of wood turning The piece has
now TO b shorened 70 ts rsquirsa length;
intsnded 70 BE- whom nnisued This extra isnglh :
.ddsd N .he ould for the purpose q making sure st
so w shS .
removed b. ssasicnary tool. assinss which me 80.
varies va | lrom thrss and half g four '' feet N
length when % ,sis ., 10 taken @ or i can b
op the soses !, s
Of the gun when IN the mould IL is much smaller in
diameter than shs bore ore q the piece s intended . BE-
.he size called for BY the cabrs Of the 10 effect
this boring rod is introduced At the muxzle after the
surface OF the piece Is being turned and smoothsc.
this angur-liks implement is gradually working
ing iis bore the necessary dimensions. When
this 10 done the inner surface is poShed, and the
through WITH !. e. pOynS can two ns SHss
from the city where the rssstive force Of the piece
put 70 the ssverest test charge Of ammunition muclr
q s.o thing. must now take paes-eliGsr the gun
.A IL any 'Ss other event, shas h1' gun wsad 3:
rather hard to locate The proof firing having
inspsc o. has BEEN once inspected sssr coming from
the foundry and Il becomes the property Of the United
q piece 20 rs delivery % sSe . for ssp
inch gun, six weeks; for nfteen.inch columbad, nx
The capacity Of the Fort Pitt Foundry may b. Judged
from the following statement Tho number OF hands
employed In all It's departments h in the neiehborbood
OF two hundred. Six air furnaces are ueed In melting
the iron, the united melting capacity Of which
hundred TONS Thirty mammoth lsthss are employed in
ceive Their motive power from double engine having
two eighteen inch cylinders and two feet stroke OF ps
70 'nsn oS. IN E.en q ~.
huge cranes eight u number has separate engine
The pits for casting are fifteen ia number and each one
10 capable of receiving tho mould Of large coiumbiad
The ground floor Of me foundry q wel e the yard
purpose Of conveying the guns in any a'rsc-
tion. Everything in nne is II The most com
and the establishment can turn out o. many Rodman
Dahlren pieces Ghe only kind IL casts - the gov
sitssn.inch srmy gun. Is now being finished ap--sss
nnt OF . new order received from the United States
S. not GD n Ss ,ss ss
government in determining on acrsassd fortnoasion
Of the foundry which q The only whore
twenty-inch guns can b oasl Besides casting guns,
government With shells and cannon Sss he skss are
cast In separate moulds; but the balls cast in cuse
when :Sa s:y via y ssSs '
Besides The work demanded for ihs United stsss gov.
eminent. however, considerable quantity is soms-
times manufactured for other nasioaA The authorities
the manufhcturc Of quantity Of ordnance for eescoa
defence, and this order is now being completed BIZ
sleveu-nch army guns Of the DahlgTsn pattarn have
been Anished and four pieces Of nsennch and twelve
Of nipe-nch (DahIgrsns) arc In procs9 Of conpsdon
Besides these . numbsr q nine-inch shell have oeen
and being boxed up tuschsgsd Of ooursel
for shipment Zach cue Of thess has g . msapPed
transvsrsey With Gin strips which are al fastened -
the lower end upon wooden sabsl Attached 70 this
tinwork 10 ropsyarn handle for each she'll oy Which
n lIftsd into she gun when required. the vpubfee
South America might profit By this foundry. HAA
such oolamSlsds = .so's ..I,,s nov nsrs s ana :
ths vantcu and almost total dsstruclon Of Che's pn-
cipal seaport ~ Spanish nsot would NOT have bssn
natter of face sccompiishmenk When . proper AlsL
position shaI have bssn made of ths ordnancs NE
Chilean eoast any opposing imperial force win have
repubcan-born bulldogs Of Iron The coss n hnishsd
runs Il about ten csuts per pound for small and twenty