THE 110YAL ARTILLERY INSTITUTION. 
219 
over the charge. Inattention to this principle, or its sacrifice to other con¬ 
siderations, is a source of weakness in many B.L. guns. One advantage of 
an open end is, that the metal of the inner tube is relieved to some extent 
from longitudinal strain. 
The relative cost of large ordnance made in different ways is approxi¬ 
mately as follows :— 
£ £ 
Cast-iron guns . 21 per ton. I Krupp’s steel guns ... 170 per ton. 
Armstrong built-up do... 100^ n | Gun-metal do. 187 n 
The latter guns (bronze) are valuable for re-casting. By the adoption of 
the modifications proposed by Mr Praser, the cost of built-up ordnance 
will, it is said, be much reduced, viz. to £40 a ton with a coiled inner tube, 
and to £55 a ton with a steel tube. Mr Whitworth's guns, like all steel 
guns, must be very expensive; he told the Committee on Ordnance that 
his 5 \ -inch gun, weighing four tons, and made of homogeneous metal 
(soft steel) costs £700, which is about £175 per ton.f 
The following will be, I think, considered sound conclusions on this 
part of the subject:— 
A cast-iron gun strengthened by hoops on the outside will fail when rifled, 
but by placing wrought-iron or steel tubes inside, better results may be 
expected. 
A heavy rifled gun made in one mass either of cast steel or of forged iron 
cannot at present be trusted. 
By properly disposing and adjusting together a few pieces of moderate size, 
a heavy rifled gun can be produced, possessing great strength and endurance, 
at a moderate cost. 
The best material for the bore, as also the safest way of closing the inner 
tube, are still open questions. 
Both coiled iron and steel will probably answer for the inner tube; for the 
exterior portions of a gun, however, there can be no question but that 
wrought-iron is the best, as well as the cheapest, of the two. 
Yarious opinions are held as to the relative advantages of breech and 
muzzle-loading ordnance, but the latter would appear to be the best adapted 
to general service, as they are stronger for equal weights of metal, and 
simpler in construction. The advantages of loading cannon at the breech 
are—that a projectile of larger diameter than the bore can be used, and its 
axis will consequently be stable; that the gun can be loaded when run up, 
the gunners being therefore less exposed; that the gun can be worked in a 
smaller space (than a M.L. piece); the cleaning of the bore can be more 
readily effected, and any ignited substance left in the bore can be seen and 
removed; also, there is no danger of the shot not being home . This plan, 
however, is attended with the following disadvantages, viz. that the 
construction is more complicated than that of a muzzle-loading piece; that 
if the gun be of large calibre, the breech-loading apparatus, when sufficiently 
[vol. v.] 
* Lately about £87. 
f Report, p. 108. 
29 
