The Sun.
London, England, 1855-07-23 00:00:00

well in them as it is found to do in small arms ; expe-
rience proves, however, that projections, on iron shot
and shed, from the unyielding nature of the metal, are
broken off in the discharge, or that the grooves in the
gun are destroyed, in either of which cases the objec
sought to be attained is, of course, defeated. The Lan-
caster gun is an attempt to obviate these difficulties, by
means which will be readily understood, if the principle
of construction of the two-grooved rifle is kept in mind.
Suppose the grooves i❑ One of this kind of rifles to make
a half turn in the length of the barrel, it is easy to per-
ceive that if the edges of the grooves were removed, so
as to render the interior of the barrel smooth, its form
would be that of an ellipse, of which the minor axis, if
perpendicular at the breach, would be horizontal at the
muzzle, and vice versa. This is the principle upon which
the Lancaster gun is constructed ; the bore is slightly
elliptical, the difference between the major and minor
axis being, as will be perceived from the dimensions of
the shell, only of an inch. A very little considera-
tion will show that when a Lancaster gun is discharged
one of two results must be arrived at, either the shell
must make a half turn during its passage to the muzzle
of the gun, or, becoming fixed iu its passage, must
burst the gun. The frequency of the latter contingency
seems to point to its being a less safe gun than the
old style of artillery, while the reported eccentricities
of the shell would appear to indicate that the rotation
imparted to it is not long retained. Probably an in-
creased familiarity with the requirements of this monster
gun may enable our artillerymen to provide for its pe-
culiarities.

We now come to the mode in which the shells are
made. In the building already described there are a
large number of furnaces, with nine steam hammers,
varying in weight from one to three tons. There are
also a number of lathes and other machines for impart-
hie. motion, in which steam power to the extent of 100
horses is required. The first step in the process con-
sists in making a plate of iron of about two feet square
and one inch in thickness red hot in a furnace ; while in
this state it is conveyed to a machine which rolls it into
the form of a cylinder, the edges lapping over, and
being securely wedded by the action of a steam ham-
mer. The cylinder is then again heated to redness,
placed upon a mould of the required form, and put
under a steam hammer, which, by repeated blows,
closes up one end. In this state the incipient shell
is conveyed to another set of hands who, again heating
it, subject it to the action of a machine, which, by enor-
mous pressure, gives to it something of its destined coni-
cal form. After again visiting the furnace the shell
belonaes the object of the delicate attention of a ma-
chine, among the most ingenious that has ever been
constructed. In the centre of a circular iron stage is a
small, well-like receptacle into which the shell is
dropped. The men in attendance then cause a huge
iron hand to descend upon the shell,, the fingers of
which, grasping the red hot mass, force it down to the
bottom. Beneath the well are four other massive pieces
of iron, which keep moving with a sort of tremulous mo-
tion, and act as the human hand in ultimately bringing
the shell into its final form. They press it, coax it, and
handle it in the most endearing manner, much in the
same way as a baker would mould a loaf into shape.
Having; finally given the required form water is
thrown into the well, and the shell withdrawn. Ix
this state the front end of the shell has been
brought to a sharp point ; in the next stage this
point is cut off, and a gun metal " bush " is fitted into
it for the purpose of receiving the fuse. The shell is
now heated for the last time, and submitted to the
pressure of a pair of oval-shaped dies, which squeeze it
into the elliptical form necessary to fit the bore of the
gun. Each shell weighs, when charged with powder,
about one hundred pounds, and their cost is stated to
be from 50s. to 60s. each. When made by hand, they
are said to have cost the enormous sum of 301. each.
About two hundred shells per day is the average rate of
working of the different machines.

The boring of the guns is carried on in another part of
the works. In consequence of the unequal cooling of so
large a mass of metal, the bore of the gun is not formed
by a core in the casting as might be imagined. If thus
cast the interior would be porous and spongy; to obviate
this, each gun is cast solid and bored out by machinery.
—Obse, Ver.