118 Guns and Projectiles. 



loss from this source. Tlic practical question therefore is, how- 

 to communicate a high velocity of rotation with the smallest 

 amount of friction, and up to the present time this problem has 

 been most successfully solved by Mr. Whitworth. In an experi- 

 mental barrel, twenty inches long, Mr. Whit worth made twenty 

 turns, so that when the projectile was fired from it, the rotation 

 velocity was much greater than the velocity of the forward move- 

 ment, and yet it penetrated seven inches of elm. In a paper quoted 

 by Sir Emerson Tennent, Mr. Whitworth says, that " in some 

 projectiles I employ, the rotations are 60,000 a minute. In 

 the rotation of machinery 8000 revolutions a minute is ex- 

 tremely high, and considering the vis viva imparted to a pro- 

 jectile as represented by a velocity of rotation of 60,000 

 revolutions, and the velocity of progress 60,000 feet per 

 minute, the mind will be prepared to understand how the 

 resistance of thick armour plates of iron is overcome, when such 

 enormous velocities are brought to a sudden standstill." Tlic 

 smallest amount of friction will take place between smooth, 

 nicely adapted, perfectly clean and well lubricated surfaces, 

 fitting tight enough to prevent the escape of the gasses that 

 impel the projectile, but not jammed against each other with 

 needless force. The inside of a good rifle should therefore 

 have a shape that is easily kept clean, and in this respect 

 Mr. Whitworth's modified hexagon, and Mr. Lancaster's oval, 

 possess an advantage over all intricate groovings. 



A cannon is merely an enlarged shoulder gun, to be fired 

 from a mechanical stand, instead of from the human body, 

 It however presents peculiar difficulties in its requirements. 

 In the first place, its size is an obstacle to perfect workmanship. 

 It is comparatively easy to forgo a rifle barrel weighing from five 

 to eight pounds, without any flaws or defects ; but the same 

 process cannot be repeated with the same certainty with a barrel 

 weighing several hundred-weights, or tons. The past iron 

 ordnance was an attempt to make quantity of material a sub- 

 stitute tor quality, which had to be abandoned when greater 

 perfection of performance was required. Then homogeneous 

 iron carefully forged, together with various modes of strength- 

 ening the barrel by additional layers of metal, either welded 

 on, or simply forced on in close contact, had to be resorted to. 

 An interesting work might be written on this part of the ques- 

 tion, and on the various modes that have been adopted with 



greater or less SUCCesSj \>\ii we nm;-t not pursue the subject 

 I10W, Or we should be led too far away from other considerations. 

 Let us pass to a Becond peculiarity in cannons as compared 

 with muskets — the necessity for tiring hard iron projectiles, 

 instead of soft lead, that readily accommodates itself to rifle 

 grooves. If a cylinder of had or any other soft metal is 



