ICO 
POPULAR SCIENCE REVIEW. 
erroneous idea, that an elongated rifle projectile has a much 
greater initial velocity than a round shot. A little considera- 
tion will show that this is not the case. With the same pres- 
sures acting through the same spaces, that is, similar charges fired 
under like conditions, the velocities of the shot will be inversely 
as the square roots of their weights. Besides which, in the 
case of the rifle, there is the work lost in friction and in giving 
the rotation. Where the rifle does gain, is in this ; that whereas, 
cceteris paribus, the initial velocities are inversely as the squares 
of the weights, the resistances of the air rise in a much higher 
proportion than the squares of the velocities, when these are 
high. A limit is, therefore, reached beyond which it is useless 
to increase the velocity of the round shot, and which it is 
possible nearly to attain with the rifle projectile. The following- 
table, extracted from the “ Lectures on Artillery,” by Major 
Owen, R.A., and Captain Dames, R.A., at the Royal Military 
Academy (from which work we also, by their kind permission, 
copy the drawings of the gun and fuzes), will illustrate these 
remarks, showing, as it does, that at first the higher velocity of 
the 12-pounder round shot gives it the advantage over the 
Armstrong. 
RANGES AT ELEVATIONS OF— 
Point 
Blank. 
1° 
2° 
3° 
4° 
5° 
12 -pounder Armstrong,) 
weight 6 cwt., charge > 
1 lb. 6 oz ) 
300 
600 
900 
1,200 
1,500 
1,600 
12-pounder (service), ) 
weight 18 cwt., charge > 
4 1b ) 
300 
700 
1,000 
1,200 
1,400 
1,600 
This table, moreover, does not fully express the difference in 
initial velocities of the two shot ; for, paradoxical as it may 
appear, the ranges of the elongated projectile are, up to about 
6° of elevation, absolutely greater in the resisting atmosphere 
than they would be in vacuo ; for the elong-ated shot, from its 
rotation, retains the same inclination to the horizontal plane 
throughout the flight, and consequently acquires a continually 
increasing obliquity to the curve of its flight. And the effect 
of this obliquity is, that the projectile is in a measure sustained 
upon the air, just as a kite is supported by the current of air 
meeting the inclined surface ; and its descent being retarded, it 
has time to reach a greater distance. At least this is Sir W. 
Armstrong’s explanation, and there is no doubt that whereas 
the 12-pounder with an initial velocity of about 1,600 feet per 
