The Sun.
London, England, 1862-10-07 00:00:00

PENETRATION OF PROJECTILES.

At a meeting of the British Association held
yesterday, Mr. T. Aston, M.A., read a paper on
" Rifled Guns and Projectiles adapted for attacking
Armour-plates." After alluding to the interest with
which the contest between artillery and armour-
plates has been watched by the country, he ex-
plained what was the actual condition of this im-
portant question so late as May last by quoting a
statement made by Sir W. Armstrong at a meeting
of the United Service Institution on the 20th May
last, as follows :—" It certainly may be said that
shells are of no avail against iron-plated ships ; but
on the other hand, I may say that neither 68-
pounder nor 110-pounder guns, with solid round
shot, are effective against such iron vessels. The
fact is, what we want is a gun, in addition to our
110-pounder rifled gun, especially adapted for
breaking through iron plates. That is what we are
in want of now." This candid confession is start-
ling when it is considered that long ago France
armed her Gloires and Normandies with rifled 90-
pounders proved to be efficient against iron-plates,
and it caused the country serious anxiety to hear
hex; Majesty's Ministers state, as they did in Parlia-
ment last Session (of course on the authority of their
scientific advisers), that after all the vast expendi-
ture upon our new artillery the navy of England is
compelled to arm her navy with the old smooth-bore,
and that is the best gun the navy actually possess,
though declared by Sir W. Armstrong to be so
inefficient. Such being the state of the question a
few months ago, Mr. Aston proceeded to consider,
first, the reason why the artillery hitherto employed
in the service (including rifled guns and smooth-
bores) has always failed to make any impression on
the plated defences at ordinary fighting range, and,
secondly, by what means artillery science has lately
reconquered its lost ground. Three conditions were
laid down as necessary to enable artillery to attack
successfully armour-plate defences-Ist, the projec-
tile must be of the proper form ; 2d, of the proper
material; and 3d,be propelled from a gun able to give
it the necessary velocity. The artillery of the Ord-
nance committee failed because theyutterlyneglected
the first two conditions and had recourse to the
brute force of the smooth-bore for the third. The
expression accepted as representing the penetrating
power of shot was " velocity squared multiplied by
weight," but the form of the shot and the material
were conditions altogether omitted from the expres-
sion, and the importance of the omission will be
obvious at once if an analogous case, say a punch-
ing machine employed to perforate wrought-iron
plates, be taken. What would be the result if the
punch which is made of suitable shape and material
were removed, and a round-headed poker of bril-
liant cast-iron or soft wrought-iron were substituted
in its place ? The great importance of velocity was
conceded at once, it is a aim qua non condition, but
there has been great misconception in supposing
.that the old smooth-bore gives a greater initial
velocity than the rifled gun, as the results obtained
will show. The average initial velocity of the 68-
pounder is, in round numbers, 1,600 feet per second,
with a charge of powder one-third the weight of
the shot, the length of the shot being, of course,
one calibre. Sir W. Armstrong stated that, with a
charge of powder one quarter the weight of the shot,
he obtained with his rifled gun an initial velocity
of 1,740 feet per second. He did not state the
length of his projectile. Mr. Whitworth, with a
projectile two calibres long, obtains an initial velo-
city of 1,900 feet per second, and with a projectile
one calibre long, like that of the smooth-bore, an
initial velocity of 2,300 feet per second, being greater
than that of the smooth-bore in the proportion of
23 to 16. The following table shows the actual
results obtained by various guns :