When a projectile is fired from a gun, it encounters the same atmospheric resistance, in proportion to its velocity and mass, as is encountered by a meteorite, the resistance increasing in a ratio something like the square of the velocity. When a battleship fires a 12-inch shot at another war-vessel ten miles away, the velocity is greatly reduced during flight, for an enormous amount of energy is consumed in punching a 12-inch hole ten miles long through the atmosphere. Gravitation, also, is drawing the projectile toward the earth with a constant pull of half a ton, to counteract which the trajectory must be made an upward curve. This makes the path longer, and consumes additional energy in raising the projectile to the top of the trajectory. If a projectile could be thrown from a gun at a velocity equal to that of a meteor, it would blaze like the sun during flight, for the metal upon its surface would be fused and gasefied by the resistance and friction of the air. It would not make any difference whether it were made of the toughest, hardest tempered steel, or whether it were made of soft iron. The velocity would be so great that it would pass through the heaviest armor-plate without appreciable reduction of speed. If the projectile were of lead, it would require armor-plate of a greater thickness to stop it than if it were of steel, for the reason that its mass or weight for its bulk would be greater. Distance and the intervening air are our most efficient protection. No armored defense now employed is wholly effectual, except the range be long. By consequence, then, future naval battles will be decided more and more by speed and size of guns, rather than by armored protection. Were two modern dreadnoughts to battle at as close range as did the _Monitor_ and the _Merrimac_, immediate destruction would be mutual. They would cripple each other more in four minutes than did the _Monitor_ and the _Merrimac_ in the four long hours during which they pounded each other. The _Alabama_ and _Kearsarge_ fought for more than an hour, within bowshot of each other, before the _Alabama_ was destroyed. Were two of the biggest and most heavily armored battleships in the world to fight today at as close range, one or the other of them would be destroyed in a very few minutes. The projectiles fired from the monster naval guns now weigh many times as much as those thrown from the guns of either the _Monitor_ or the _Merrimac_, and these huge projectiles have also a multiplied velocity. The total thickness of the armor of the _Monitor's_ turret was ten inches. An iron wall of the character used in Ericsson's turret, five feet in thickness, would not afford adequate protection against our modern, monster guns.