'The views and opinions of Brigadier General John Jacob, CB. Aide-decamp to the Queen; Aide-de-camp to the Governor General of India, &c. &c. &c.; late commanding in chief the British forces in Persia; at present commanding the Sind Irregular Horse, and Political Superintendent of the North-West frontier of Sind.' [‎235] (266/481)

235
Memorandum No . IV.
Foi cannon, especially field pieces, similar shot to these
found so effective for small arms might be used, perhaps,
with advantage, instead of the shot, with wooden bottoms'
formerly proposed by me.
The only objection seems to be the cost of the lead ;
which, however, would not probably be very great, as the
quantity may be much reduced by making the dove-tailed
tenon of the iron larger.
Shot, parity of lead, for rifled cannon, have been, I
understand, not long ago tried, and found to fail, at
Woolwich; but these proposed by me are of entirely
different construction, and seem free from the defects of
the others.
Nothing but actual trial can decide the merits of these
things; and if such trials be made, it should be borne in
mind that great weight is essential to the correct perform
ance of rifled cannon. The observations on the vibrations
of the barrels of small arms tell here with redoubled force.
Strength to resist the bursting force of the powder is
by no means sufficient—weight and mass are required ;
and, whatever the strength may be, the rifled cannon should
not be of less weight than one hundred and twenty times
that of its shot.
Judgmg from experiments made, as an old artillery
officer as well as a rifleman and practical mechanic, I am
deliberately of opinion that a four-grooved rifled iron gun,
of a bore of four inches in diameter, weighing not less
than twenty-four hundred-weight, could be made to throw
shot to a distance of ten miles and more with force and
accuracy.
The " Lancaster" guns must, I think, fail. The mode