Page:Our big guns.djvu/15

( 9 ) infinite, so that the effect of gravity could not come into play, the gun could be laid point blank on the object to be hit, and we should then get far better shooting than we get now, wonderfully good as that shooting is. But owing to the necessity of giving the gun elevation, varying with the velocity and the range distance, the success of the shot at long ranges is sadly dependent on the powder; a little difference in the moisture, for example, may cause the shot to exceed the normal velocity, or to fall off therefrom by a few feet per second, with the result that in passing along the curved line of flight, which the combination of the gun's elevation and the action of gravity has imposed on it, it is submitted to this action of gravity for more or less time, and the shot will therefore either pitch beyond, or fall short of the exact spot intended to be hit.

Now it is obvious that the form of the projectile must have a great influence upon the question, whether or not the muzzle velocity shall be rapidly diminished, or shall be fairly maintained. No one can doubt that if there were two bodies of equal weight, one made in the form of a javelin and the other in that of a flat disc, and if both were cast from the hand with equal velocities, the disc being propelled flatways against the air, that the javelin would retain at the end of a given time, much more of its initial velocity, than would be retained by the disc. Similarly with the projectile.

To revert to the 68 lb. 8-inch sphere with its muzzle velocity of 1600 feet per second: at the end of 500 yards of flight this velocity would have fallen to 1200 feet, and at the end of 1000 yards it would possess a velocity of only 950 feet. But if we were to adopt the javelin principle, even although we made a very blunt one, viz. if we were to put our 68 lbs. into the form of a cylinder (with a Gothic arch-shaped head) having a diameter of 5 inches with an extreme length of about 15 inches, the muzzle velocity of 1600 feet would at 500 yards be 1480 feet, and at 1000 yards would be 1360 feet.

But another advantage would ensue from disposing this weight of metal into the form of a long small cylinder, instead of into