found. Excellent throughout, it is told with
a singular propriety, modesty, clearness, and
force.

STRONG GUNS.

IF there arose in this country a great magician
who, by the magic of genius joined to intense
labour, solved every unsettled question that now
stands in the way of our knowing how to make
an absolutely strong and serviceable field gun,
what would his chance be with the Ordnance
Select Committee? So many minds are now
devoted to gun-making, that about thirty inventions
a week come before that committee for
discussion. This committee consists of specially
informed men, who, as we are quite disposed
to believe, do their best. But the subject is
one about which the wiser a man is, the more
numerous are his uncertainties. As for the
test of proof, it is notorious that an inventor's
gun bursts only because of one out of a
thousand reasons that do not affect the credit
or the principle of the invention. There is a
rush against the old cast-iron artillery; the taste
of the day is for guns that are built, not cast.
But who shall be gun-builder? We read the
other day, that the bursting of a large gun at
Dover had destroyed several artillery volunteers,
including the coroner who should have held the
inquest on the killed, and, in the same
newspaper, the false news that Mr. Whitworth's ideal
of a piece of ordnance had been rejected by
the select committee. Sir William Armstrong
does not pass uncriticised. We are not suffered
to settle down in the belief that it is he who is
the happy benefactor of his country. As for the
Lancaster guns, how they burst!—for reasons, of
course, that have nothing to do with their merits.

There were held, early in the year, half a
dozen meetings of the institution of Civil
Engineers, at which, on the test of a paper by Mr.
James Atkinson Longridge in exposition of his
own view of perfect artillery, nearly all the
great authorities on the subject of artillery and
the inventors entered into discussion with each
other. Hardly an opinion was expressed that
was not contradicted, and we might almost add
no fact was stated that was not denied. The
paper and discussion, giving the best extant
view of the pros and cons of one of the great
questions of the day, have been edited by Mr.
Charles Manby and Mr. James Forrest, the
Honorary Secretary and Secretary of the
Institution, in a book which we have read carefully
through. We have got out of it, a lively sense of
the sufferings of the select committee, that must
sit in judgment upon questions so unsettled.

Questions of range and aim are easily disposed
of. It is almost admitted that the round shot
from the old-fashioned artillery has in the beginning
of its course a swifter pace than the shot
from a rifled gun, and that it is, for close firing, to
be preferred: while the long ranges are obtained
by means for securing an extreme force of
gunpowder which have to be borne and resisted by
the metal of the gun itself. The gunpowder
manufacture in this country has been so much
improved that its explosive force is greater than
that of the powder made for governments
abroad. Also, we test guns to extremity by our
new ways of using them; in experiment we
test them wilfully to the utmost, by adding
steadily to the force of the explosion until we
discover what strain they will bear before they
burst. The great unsolved problem is, to find
a gun that is not to be burst by any force of
gunpowder. The force of gunpowder being first
ascertained, and the strain that solid substances
will bear, being also known to the engineer—how
to construct a gun that will bear more than the
utmost possible strain produced by the explosion
of gunpowder, is the question.

But the explosive force of gunpowder, a
knowledge of which is the first condition of
inquiry, has not been settled yet by the philosophers.
It has been variously estimated at
anything between seven and seventy tons to the
square inch. As Captain Boxer said, in the
course of the discussion, "notwithstanding the
most careful calculations, involving the highest
order of mathematics, made by those practically
acquainted with the subject, no satisfactory
results had yet been obtained." The gentleman
who opened the discussion fixed it at seventeen
tons on the square inch. Mr. Bidder, the President
of the Institution, had calculated it at
twenty; Mr. Vignoles found it often nearer to
thirty; and Professor Airy had thought that
under certain circumstances the force was much
greater. One great authority attributed to
gunpowder, two forces: one statical, and one
percussive. To which an equally great authority
replied, that statically a pound of gunpowder
cannot do more to generate speed than a pound
of butter, and that if it were to act percussively
it must destroy both shot and gun.

As to what might be determined upon the
strength of material, the results of experience—
and most clearly in the case of cast iron—appear
to vary within quite as wide a range. The
settled fact, however, is that the construction of
gunpowder-proof artillery is a problem of which
the solution, sure to be attained some day, seems
to be only just beyond the reach of science in
the present hour.

Also there is an admitted theory to work upon
if necessary. It is being worked upon more or
less closely, by recent inventors of artillery; but
there are men of authority who, while they admit
it, hold that for divers reasons we gain nothing
by its application. The discussion to which we
have referred was opened by Mr. Longridge,
with an account of an invention based upon that
theory, and admitted by all disputants to represent
the most complete acceptance of it.
Roughly expressed, the theory is this:—Metals
have in their way, like india-rubber, tensile
power, and when strained beyond it, they are
broken. Now, in a solid cast-iron gun—assuming
it to be uniform throughout—when the discharge
takes place, the greatest strain is on the inner
surface, and the strain lessens as we advance to
the outside, through the thickness of the metal;