The rotation of the earth about its axis tends to throw the projectile always to the right of the object aimed at. Space will not permit of our entering on this subject; but the principle is the same as that which in M. Foucault's experiment with the vibrating pendulum caused its plane of vibration apparently to constantly deviate to the right. The time of flight of the shot from Mr. Whitworth’s 3-pounder gun is unknown to us; we are unable, therefore, to calculate the deflection due on this account, but as an illustration we may give this deflection, calculated for the long range attained with the 10-inch gun (5,600 yards), from Captain Boxer’s, R.A., _Treatise on Artillery_. He finds it to be very nearly 11 yards. Windage, one of the faults of the spherical bullet, permitting a great escape of the gas, and therefore wasting the force of the powder, has been overcome in various ways in the cylindro-conical picket. The Minié principle consists in hollowing out the base of the ball conically, placing in this hollow an iron cup or piece of wood, which being driven forward by the explosion of the charge further into the conical hollow, enlarges or expands the ball, and makes it fit tight and take the impression of the grooves, though the bullet, when put into the gun, is small enough to be easily rammed down. It is now found that the conical hollow alone, without the cup or plug, is almost equally effective in expanding the ball. We have termed this the Minié principle; Captain Norton, however, undoubtedly has a prior claim (which has been allowed by the British Government, we believe) to this invention. He was before his time. There was no cause for, and therefore the shooting mania was not strong upon us. With breech-loaders, doing away with windage and making the bullet take the rifling, is an easy matter. The breech into which the bullet is put at once, without being passed through the muzzle, is made slightly larger than the rest of the bore; the bullet on being pushed forward by the force of the powder is squeezed into the narrower portion, and effectually prevents all escape of gas. It is thus with the Armstrong gun. Robins said of the breech-loaders of his day, “And, perhaps, somewhat of this kind, though not in the manner now practised, would be, of all others, the most perfect method for the construction of these barrels.” Mr. Whitworth, on the other hand, uses—well, we have avoided details thus far, and every newspaper has described them so fully, that our readers must be thoroughly acquainted with them. Let us conclude, as we began, with Robins, and hope that his prediction that “they,” the armies of the enlightened nations which perfect rifles, “will by this means acquire a superiority which will almost equal anything that has been done at any time.” FOOTNOTES [15] It is not at all certain whether Marriott’s law of the elasticity being as the density is true, when the gases are so highly condensed.