know much more when we hoop Armstrong guns,
than they did of old who hooped Mons Meg and
fired out of her more than three hundred pounds of
granite in a lump. Cannon formed of prismatic
bars of wrought iron hooped together were known
in the old times of India, the oldest nation known.

Mr. Longridge begins by recalling the names
of Robins and Hutton from the past, and citing
those of Nasmyth, Whitworth, Mallet, and
Armstrong in the present. He describes his plan
of a wire gun, and expounds it theoretically on
high grounds of mathematics. The experimental
gun that failed, was a mere specimen cylinder of
which the end was blown off, as predicted. He
has plugged close cylinders with government
cannon powder, and has found that a cylinder
with ten coils of wire on it could not be burst.
Our improved gunpowder tries guns. A shot
fired with John Chinaman's powder, General
Anstruther said in the subsequent discussion,
was sent three hundred yards, and a like shot,
impelled with John Bull's powder, went twelve
hundred yards. "It is said," observes Mr.
Longridge, "that no sixty-eight pounder in the
service can now be fired with safety with a full
charge of powder. Our powder in old days was
slower of combustion than it now is. We must
not ascribe, therefore, to their being more
dishonest traders now than of yore, the more
frequent bursting of guns in the present day."
Several best authorities add the fact—if it
be one, for several as good authorities deny
it—that a cannon just made is more likely to
burst, than a cannon that has been set aside
unused for a few years after its manufacture. In
the United States, guns of the same description,
tried thirty days after casting, burst after about
eighty rounds; one, kept six years, endured
eight hundred discharges before it burst;
another, fired two thousand five hundred and
eighty-two times, had not burst at all. Again,
in old days past, their charge of powder was
blown out of the guns unconsumed; now,
thanks to the tightly fitting shot, every particle
explodes before the shot has left the chase.

Then, as to the material of cannon; Mr.
Longridge recals the bursting of a steel gun of Mr.
Krupp's at Woolwich, to which it is replied
afterwards: This was because the gun was designed for
a sixty-eight pound shot, and a shot weighing two
hundred and sixty pounds was used. A twelve
pound howitzer of Mr. Krupp's had been tried
to the utmost, till it was itself blown high up
into the air by the force of explosion, but it was
not to be burst. There is no certainty about
cast iron; in one case, a cast-iron gun sustained
fifteen hundred or two thousand rounds: while
another, said to have been cast from the same
metal, under precisely the same conditions, did
not last out a day. Mr. Longridge looks upon
wrought iron and steel as improvements in
material that do not touch the real defect, but which
leave us with the want of a gun like his wire
gun, that is mathematically adjusted to the
different degrees of strain suffered by each part
of its substance in the moment of explosion.
Mr. Mallet, Captain Blakely, and others, had
fallen upon Mr. Longridge's idea. Five years
ago, he adds, when he mentioned the principle
to Sir William Armstrong, and his method of
applying it, that gentleman said Mr. Brunel had
also entertained the same idea, and had spoken
to him with reference to making a gun on this
principle, but finding another man engaged on
it, had dropped the subject.

Mr. Longridge's method, in practice, was to
coil a quantity of wire on a drum, fixed with
its axis parallel to that of a lathe on which the
gun was placed. On the axis of this drum,
there was another drum, to which was applied
a break so adjusted as to give the exact tension
proper for each coil of wire. Accuracy of
tension with hoops Mr. Longridge regards as
impracticable. The process of shrinking on, he is
convinced, is not to be depended upon. In his
own method he looks upon the inner cylinder,
about which wire is coiled, "simply as a means
of confining the gases and of transmitting the
internal pressure to the wire." His principle
is, of course, applicable to the cylinders of
powerful hydraulic presses. And five or six
years ago, Captain Blakely, in the specification
of a patent for ringed guns, referred to an outer
covering of wire, or rods wound spirally in one,
as means of strengthening old guns.

Mr. Longridge's theory passed the debate
undisputed, though for reasons already cited there
was little expression of faith in the power of
applying it. Mr. Bidder, the president, did not
forget to remind the debaters, that wire could
not only be applied with the greatest ease,
exactly in the way indicated by theory, but that
it is the strongest material known. Iron bears
twice the strain as wire, that can be safely
applied to it when in the bar.

Mr. Gregory, who had been for two or three
years a member of the Select Committee of
Ordnance, thought that the hooped guns, if
less perfect theoretically, were less liable to
subsequent injury. Several disputants, indeed,
suggested that if a wire gun were to be hit by a shot
of the enemy, and three or four wires were to be
broken, it would be disabled. Mr. Longridge
denied that. He would also bind his wires with
solder, and protect them under a cast-iron
sheath. Captain Blakely described trials
withstood by his cast-iron gun, with three wrought-
iron hoops shrunk on it. It was fired at
Shoeburyness during nineteen months, and it proved
by seven to one more durable than the cast-iron
service gun, and three times better than the
brass gun. But he agreed in praise of wire, and
said, "Indeed, if monster cannon were wanted—
mortars to throw several tons several miles, for
example—recourse must be had to wire."

Mr. Britten then told his experience as to the
rifling of our ordinary service guns. It enabled
shot half as heavy again to be used, conical
instead of round, which might be shells able to
carry a bursting discharge three times as great
as that of round shells. The smooth bore gun
varied in a range of twenty-seven hundred
yards, as much as twenty-three yards from the
line of aim. The same gun when rifled, at a