The war-officer condemns and casts out. But
Major Palliser steps in, scoops out the interior,
re-lines it, and makes it—not as "good as new,"
but literally far better than new. All, too, for a
sum ridiculously low. At home in store, in
dockyards, on old towers and fortifications, up and
down here and there through the kingdom, out
in the colonies, in ships and in cellars, even on
the terraces of noblemen's castles who wish to
have a little cheap military show, and hold these
old "pieces" in trust for the War Office, are
tens of thousands of this old ordnance, of all
sizes and dimensions. Every day, the list is
being swelled; for, every day salutes and reviews
are putting a term to the services of many of
the monsters. The question arises, should not
these be considered rather as damaged than worn
out, which, in fact, three-fourths only are—a
damage that literally a pound or two can repair.

One of the old vulgar errors—and it is a vulgar
error still with many—was, that thickness was
strength. You made an enormously thick cannon,
and you had, therefore, an enormously strong
cannon. Experiment has now discovered, first,
that the shock produced by a discharge acts
chiefly at or about the breech, and that, therefore,
immoderate thickness is only thrown away
in other portions; secondly, that the shock
will only travel through a certain thickness, and
that, after that, the disturbance is not felt. The
waves of disturbance, in fact, do not go through
the iron beyond a certain distance. But there
is something more to be considered to understand
this new plan. We hear the words "cast-
iron," "homogeneous iron" "malleable iron,"
&c., used abundantly, which convey very
confused ideas. All the old artillery we see lying
in the forts were made of "cast-iron"—perhaps
the worst known iron in the world. That is, a
heap of iron was melted with all its dross and
impurities, and then "run" in a sand mould. As
the gun cooled unequally—the outer surface,
next the air, before the inner, and both very
suddenly as compared with the interior texture
—sometimes this interior, between the outside
and inner layers, never solidified at all, and has
been found to be quite soft and pulpy. A
greater danger still is what is called "honeycombs,"
when the bubbles get imprisoned in the
cooling guns, with the result of a series of
hollow cells between the outer and inner
surfaces. So that the gun is, in reality, but (say)
one-third as thick as it appears to be. Again,
cast-iron is full of impurities, is unequal in
quality and in density. But there is a greater and
almost a certain danger. If there be—what there
is sure to be—a flaw—a crack even the width
of a human nail—this is the foundation of
destruction. The powder gases act as a lever,
and at every discharge widen this little crack,
until in the end it bursts the piece itself. This
fatal crack cannot be guarded against, and on
all grounds, therefore, cast-iron is undesirable.
Major Palliser, however, collects these old
and condemned arms, places them in a turning
machine, and scoops away an inch thickness of
the interior metal, introducing a small tube or
lining, which is screwed in, and formed of
several tubes of wrought-iron or steel fitted on
each other according to his principle.

The great danger, however, is from what are
called "sets." Up to a certain point the iron
is "elastic" under an explosion: that is,
expands, and contracts again to its original state.
The limit to this elasticity stands at about four
tons on the square inch. The gun will bear a
great deal more, perhaps up to ten tons, without
bursting; but, once the strain has gone beyond
the limit of elasticity, the economy of the metal
becomes disturbed, and what is called a "set"
takes place. The whole texture of the gun has
been strained, and its strength really reduced.
By this new plan of Major Palliser's, a sort of
artificial texture is built up. The inner core
introduced is formed of a material whose power
of elasticity is nearly three times that of cast-
iron. This new lining takes all the practical
strain and duty on itself: the old cast-iron shell
takes its share, and is well able to bear the
shock that reaches it, and at least the
longitudinal pressure.

What, then, is this valuable "homogeneous"
or "Krupp" iron which enjoys such a reputation?
It is simply well-made wrought-iron—iron made
very dense. It is the most wrought of wrought-
iron. Krupp hammers the metal into a quantity
of little ingots, which are beaten into the densest
shape. These little ingots are only the materials
for making the iron, and by means of steam
hammers these are welded into masses of iron.
The hammering, in short, is so "thorough,"
that all chance of cracks, flaws, or
"honeycombs" becomes next to impossible. The
more wholesale and effectual the hammering,
the "closer" and more superior the metal.
This is the secret of the Krupp iron. But by
this process the result is so extraordinary that
a new metal seems to have been created. The
power of resistance is almost amazing, and Mr.
Whitworth is actually said to have plugged one
of his musket-barrels made of this material,
and to have fired it off without bursting the
piece. As may be conceived, it is costly. Major
Palliser would merely use a lining—and it is on
the lining, and only at the breech portion of the
lining, that the great pressure acts—and would
trust to the old cast-iron for the balance of                                              resistance.

This interior lining might be made of several
tubes. They should not be shrunk over each
other, as Mr. Whitworth does his, by hydraulic
pressure. For, by the "shrinking," the inner
tube is compressed and tightened more than it
ought to be, and, when the shock comes, will
assist in straining the one over it. Major
Palliser would make his innermost layer of very
soft and elastic iron, the next of a harder sort,
the next of steel, and the outside one of the old
cast-iron cannon itself.

This officer's name has become associated with
two other curious discoveries. One is so simple
a thing as the method of tracing the threads
of a screw to be used in targets, with astonishing
results—raising them on the surface instead