range increased by eight hundred yards or more,
varied not four yards. The country has in
stock, fourteen or fifteen thousand such guns.
Are they to be all sold off as old metal? The
rifling costs about thirty shillings a gun, and
may be done by a portable machine. The
service gun unrifled, has a recoil on the platform at
Shoeburyness of nine feet three inches, with its
charge of ten pounds of powder and a thirty-
two pound solid shot. The same gun rifled, with
a fifty-pound shell and five pounds of powder,
has a recoil two feet less. Does this confirm
the dread of risk from greater strain? The
degree of strain may depend much, upon the
nature of the projectile. Mr. Britten fits his
rifling with five thin projections of soft lead
upon the surface of cast-iron shells.

Touching the simple question of the real
cost of each kind of gun, there was almost
as much confusion of opinion as upon any
point of science. Mr. Britten's estimate of the
cost of the Armstrong twelve-pounder three-
inch gun, weighing eight hundred-weight, was a
quarter of a thousand pounds. A cast-iron
nine-pounder of twice the weight, costs less than
twenty pounds. In all close fighting the old
service guns would have the advantage of the
new inventions, except in precision of aim.
Precision of aim at shorter distances, is the
most valuable thing indicated by great length
of range. In proportion to the distance to which
the shot is sent, must be the elevation of the
gun; a shot that comes to the ground five
miles from the point of discharge, does not mow
its way like short-range shot, through hostile
ranks, but comes down from the sky, and if it
be only a solid ball, must take the little chance
it has of finding a man's head, or something else
that is worth breaking, placed exactly where it
falls. The cost of an eight-inch cast-iron gun,
said Mr. Britten, is about a hundred pounds;
and he thought it doubtful whether either an
Armstrong or a Whitworth rifled breech-loader
of the same size could be made for much less than
a thousand pounds. Between the shots used by
each kind of gun, he thought there was a similar
relation of expense. But Sir John Burgoyne
had authority to say that a penny a shot was the
additional expense of Mr. Whitworth's method
of shaping. We may remark, by the way, that
Sir John Burgoyne also valued the long-range
guns less for their mere range than for accuracy,
and for the power they had of being fired at
lower angles. Mr. John Anderson, whose
connexion with the manufacture of the Armstrong
gun gave him a right to speak, said that the
Armstrong twelve-pounder complete, now made
at Woolwich, costs, not two hundred and fifty
pounds, but ninety. Mr. Krupp's Prussian
breech-loader of the same size, made of mild
cast steel well hammered, costs one hundred and
fifty. The cost of the old twelve-pounder brass
gun was about twice as great. Somebody
afterwards observed that the old brass guns when
worn out were worth nearly their first cost as
old metal. Sir William replied to this with a
belief that his guns never would wear out.

The other gentleman who has confined his
operation to the service gun is Mr. Haddan.
He considered Whitworth and Armstrong plans
of rifling to be unsuited to cast-iron guns. The
large cast-iron guns bored on the Whitworth
system, had burst: owing, as Mr. Haddan
believed, to the quickness of the rifle twist. He
had himself fired a shell weighing ninety pounds
with a twist of about one turn in forty feet,
while the Whitworth three-pounder has twist of
one turn in forty inches. Mr. Haddan gives
this very gradual twist, not to a sharp cut, but
to a broad smooth groove, and shuts out windage
with a wooden wad at the conical back of
his projectile. When his proposition was brought
before the government authorities, there were,
he says, already before government, eighteen or
twenty different plans for rifling the service
guns. He understood that Sir William
Armstrong had made two attempts with service
guns, both of which had burst; and that Mr.
Whitworth had been equally unsuccessful. But
of several such guns rifled by Mr. Britten, not
one had burst. The guns experimented on by
Captain Scott, R.N., Mr. Jeffries, and others,
had not burst: neither had the sixty-eight-
pounder rifled by Mr. Haddan himself been
injured.

There is an important element in the strength
of cast guns, to which Captain Scott called
special attention, and as to which others
confirmed his statement. The surface of the cooling
mass after it has been cast, hardens into a
"skin," which is of great toughness, and
would do much that is now expected from the
iron bands, if we did not remove it. In reality,
we do worse than remove it when we leave
rings and patches of it round the muzzle, round
the breech, and at the trunnions, interfering with
the uniform expansion and vibration of the
particles of metal when the gun is fired. Water
in a gun-barrel, witnessed Mr. Conybeare,
cannot be forced by hydrostatic pressure through
this kind of skin. The water has been known
to get underneath it through a chance crack and
then raise the metal skin into a blister which
must break before there is free access to the
substance of less compact metal. Now, the gases
produced by explosion of gunpowder are more
penetrating than water, and their presence is
great. Obviously, then, the removal of the
inner skin from any gun cast hollow will make
it less durable. When Mr. Lancaster accounted
for the bursting at the muzzle of three of his
guns in the Crimea, he said it was because they
were not guns specially made to his design, but
service guns bored oval on his system. He
attributed the mishaps, however, to a defect,
afterwards corrected, not in the guns, but in the shells
supplied for them to fire. The shells, because of
a defect in the welding, were liable to burst inside the gun.

An improvement in gunnery, adopted already
in the American navy, is the idea of Captain
Dahlgren. He adapts the thickness of the metal
in the length of the gun, to the varying shock of
the explosion as the shot is passing on. The