Naval ordnance has made greater strides in the forty years that have intervened since the Civil War than in several centuries preceding. As proof of this it is enough to look at the striking comparison shown in the accompanying cut. The smaller illustration represents a Parrott 100 pounder of 1862, superimposed upon a modern 100-pounder, or to be correct, a 6-inch 50-calibre rapid-fire rifle of the year 1900; the lower diagram represents a 15-inch smooth-bore of the Civil War, superimposed upon a 12-inch breech-loading 45-calibre rifle of to-day. The comparison might be carried out to greater length throughout all the various calibres that constitute the batteries of naval ships; but we have chosen to compare the main battery of the monitor with the main battery of the modern battleship, and what might be called the secondary battery of the frigates of 1862 with the standard secondary battery gun of the battleship of to-day.

The heaviest piece carried in the Civil War was the 15-inch smoothbore. This gun weighed 42,000 pounds; its length over all was 15 feet 1 inch; its maximum diameter at the breech was 4 feet, and with an ordinary charge of 35 pounds of black cannon powder, it fired a spherical shell weighing 350 pounds. According to the ordnance regulations, under extraordinary conditions, these guns might be fired 20 rounds "at ironclads at close quarters," using 100 pounds of hexagonal or cubical powder and a solid shot weighing 450 pounds. Under these conditions the most respectable muzzle velocity of 1,600 foot-seconds was obtained, with a corresponding muzzle energy of 7,997 foot-tons. It would be interesting to know what the powder pressure was under these conditions, for the velocity and energy are something truly remarkable for a cast-iron gun. It is little wonder that only 20 rounds were allowed under the severe stresses imposed by these ballistics.

Now, compare these results with the most powerful gun in our navy to-day, namely, the 12-inch 45-calibre rifle, which weighs 53.4 tons, has a total length of 45 feet, and with a charge of 360 pounds of smokeless powder fires an 850-pound shell with a muzzle velocity of 2,800-foot seconds and a. muzzle energy of 46,246 foot-tons. The true basis of comparison of the relative efficiency of the two guns is the amount of energy developed per ton of the weight of the gun, and on this basis we find that the old 15-inch smooth-bore gun when fired with 100 pounds of powder developed 427 foot-tons of energy per ton of gun, as against 872 foot-tons of energy developed by the modern 12-inch rifle.

The Parrott 100-pounder rifle and the 15-inch smooth bore (period of Civil War), compared with the 50-calibre 6-inch and the 45-calibre 12-inch rifles of 1902. Civil War guns are shown in black.

Our Naval Guns In The Civil War And To-Day.

If we take account of the durability of a gun the advantage will be stronger on the side of the modern piece, for whereas the 15-inch smooth-bore was limited to twenty rounds under the given conditions, the modern 12-inch rifles, judging from the small amount of erosion developed with nitro-cellulose powders, should have a useful life of at least half a thousand rounds. Moreover, it must be remembered that the modern elongated shell will hold its velocity much longer than the old spherical shell of the smooth-bore, and, consequently, the respective muzzle velocities and energies are no criterion of the respective efficiencies of the guns.

The gun of 1862 that answers to the modern secondary battery, 0-inch rifle, is the Parrott muzzle-loading rifle, a cast-iron gun which was strengthened at the breech over the powder chamber by shrinking thereon an iron hoop. The bore of the gun was 6.4 inches. It weighed 4.35 tons, was 12 feet 4 inches in length and with a charge of ten pounds of powder it fired a 100-pound shell with an initial velocity of 1,080 foot-seconds and a muzzle energy of 810 foot-tons. Compare this with the modern 6-inch rifle, which weighs 8.5 tons, is 25 feet in length, and with a charge of 40 pounds of smokeless powder fires a 100-pound shell with an initial velocity of 2,900 feet per second and an initial energy of 5,838 foot-tons.

Compared on the basis of energy per ton of gun, we find that the 100-pound-er Parrott muzzle loader developed 186 foot-tons of energy per ton of gun, whereas the modern 6-inch breech-loading rifle develops 784 1/2 foot-tons of energy per ton of gun.