352 
MINUTES OF PEOCEEDINGS OF 
4 calibres. No Armstrong common shell is 3 calibres long; their average 
length is 2*8 calibres. This construction generally gives a greater strain on 
the gun, by the increased length of column to be moved by the elastic force 
of the gas, and the reduced area of the base on which the gas acts. 
It is not the best form for common or shrapnel shells, but is favourable to 
the penetrating powers of the shot, and Mr Whitworth has in consequence 
attained considerable success in one instance against a 4 J-inch iron plate, 
which was absolutely penetrated by a 68-pr. bolt of — diameter, at 420 
yards. 
The Committee are not prepared to say that the superior penetrating 
power of the shot is an advantage for general service which would counter¬ 
balance any decided loss of relative efficiency, in the common shrapnel shells, 
should such be hereafter substantiated; but it is undoubtedly a property not 
to be lost sight of. 
6. A rapid spiral is the proper accompaniment of a great length of pro¬ 
jectile. It is not in itself an advantage, but the reverse, bringing a greater 
strain on the gun, and augmenting the chance of the shot sticking in 
loading; but it is conducive to accuracy, and is an important part of the 
system advocated by Mr Whitworth, although not peculiarly his own.* 
7. Mechanical nicety of finish.—Mr Whitworth's European reputation as 
a machinist has naturally led to a successful endeavour on his part to attain 
a great degree of perfection of finish in his guns and projectiles, but the 
Committee believe that the Armstrong breech-loading guns and projectiles 
are equally highly finished; and as regards muzzle-loaders, the machinery 
now in the Eoyal Gun Eactories (which originally owes much of its 
perfection to Mr Whitworth's mechanical discoveries) is capable of turning 
out guns of any system that may be adopted with equal nicety if required. 
This feature, therefore, if any stress is laid upon it by Mr Whitworth, 
furnishes no reason for preferring the polygonal system to any other for 
muzzle-loading rifled guns. 
8. It remains to be stated whether the range and accuracy of the Whit¬ 
worth system is superior to other muzzle-loading rifle systems. It will be 
seen that the Committee have had but little experience of guns assimilating 
to those which are required for garrison and naval service. Eange and 
accuracy in rifled guns depend materially upon length ; this is strikingly 
evidenced, as to range, by the difference between Mr Whitworth's muzzle¬ 
loading and breech-loading 12-prs.; the latter is 36J inches, or 12J calibres 
longer than the former, and with the same charge, has a range exceeding the 
other by 250 yds. at 2°, by about 270 yards at 5°, and by about 450 yds. 
at 10°. The corresponding deflections reduced to a mean line, and 
corresponding errors of range, are— 
* So far back as 1791, experiments were made at Woolwich by Lieut.-General Parker, with 
8-grooved rifles of -61 diameter, and 1 turn in 20 inches and 30 inches. The regulation rifle of the 
period had 1 turn in 120 inches. The ball was spherical. 
