The Davenport gazette., 1851-11-13
AN HOUR IN A POWDER MILL.

AN HOUR IN A POWDER MILL.
The Pittsburgh Powder Mills are sitna
ted on the North bank Of the Monongahela
about two and half miles from the city
For the purpose Of lessening the disasters
Intending explosions. the buildings cover 4
large extent Of ground, and each Of the ma
nv processes TO which the material is sub
ject before it is turned out in form will
which the world is bnt too familiar, is per
! formed in separate building. These build
ings are stone, and are connected togeth.
er by a railway.
But to begin at the beginning. Good
gunpowder, such as MIR. Watson makes.
requires good charcoal; young and sound
wood is required, the water nipple being
| the most desirable. OF these Mr.. Watson
has large plantations which weld whit
wood he requires, besides furnishing con
siderable number Of Young trees TO the cit
izens for ornamental purposes. There esre
also on the premises plantations Of syca-
more for hoop-poles, which yield about 5.
600 per year per quarter OF an ncre. From
the plantation we went 10 the steam en-.
gine And here the dread Of fire, which
! habit has made second nature o,he pow
derm,ker, has suggested number OF iu-
genious conirivances to prevent its coming
ia contact with the svilIainous saltpetre." :"
The smoke from the fires under the boil
ers is conveyed under ground some 300
feet, and then by chimney 60 feet high
il is carried of, At supposed safe distance.
In directly the opposite direction the steam
is carried considerable distance under
ground 10 the engine, which is distant from
The place where the last processes are per
lfnrmed-which bv its aid the powder un
dergoes--some 700 feet. The engine ha.
six boilers attached to il, each 30 inches in
diameter, and % feet 8 inches long, ami
consumes about 45 bushels of conl per day.
The wood is converted into charcoal b,
heing burned in large cast iron retoris.
md the gas that is evolved is conveyed b>
pipes into the fire under the retort, b,
which one-ihird of the fuel that would 9th
erwise be necessary, is saved. The pyrn-
ieneous acid which the wood contains, and
which this process evolves, il is the purpose
of Mr.. Watson to dislil into vinegar, n
soon as his arrangements Tor that purpose
can be effected.
We followed the charcoal into the ''com-
pounding-hnuse." Here, after having been
crushed between rollers, it is placed in a
large hollow cast iron globe, in which are
= considerable number Of small brass balls; /;
these globes are msde TO revoIve rapidly.
which speedily reduces il to fine impalpa-
bic powder. II is then put with the other
ingredients, in the proportion Of Is ofchsr
coal, 10 Of sulphur, and IS Of niire, into
sinking barrel" which is made to revolve
36 times per minute.
From the mixing barrel it is taken 10 ihs
.''niI-house," where large rollers Of cas-,
iron. weighing $50 lbs each, of the shape
Of mil.stones, placed on end, chase each
other round a cast iron circle weighing
10000 lbs. Under these rollers il il crush
ed for about FIVE hours, aud then il is Ia
ken into the ''press-room." In the press
room It is put in layers between cloths and
boards alternately, and subjected to the
immense pressure Of hy draulic press.
This is done to condense the powde, into q
solid substance. The cakes or slabs nre
then taken to another building and passed
through pair Of coarsely groovcd rollers.
which break il into small Jumps. This is
The first process Of "graning."
These Jumps are then placed on shelves
in room heated by steam for the purpose
Of being partially dried, when they arr
again passed through various rollers, unit
the desired, ssgrain" is obtained. From the
rollers the gunpowder, as it may now b.
termed, passes through hopper in re
volving wire cylinder, the different degrees
of fineness in the length of which screen !,
into as many kinds Of powder; the finest,
which is mere dust, is taken back 10 bt
re worked.
The reminder 10 placed in barrels.
about $50 lbs. in each, which are made
rapidly to revoIve for the purpose Of ''gls
zing" it. But one operation now remains.
and that is the final dr., ing, which is et
lected in the manner we hive before des-
rrbed. |, is then taken into the packing
house, and from that to The s'magazine,'
which is firc-proof tuilding ! long dis
,ance from the rest of the works.