There is no subject in the development of the new naval artillery more important than the powder. That used with the old artillery is entirely unsuited to the new conditions that obtain in the modern high-power guns. A brown powder, introduced first in Germany, has exhibited decided advantages over all others, and the efforts to reproduce it have been thoroughly successful at the Du Pont Mills. It is generally known as “cocoa” powder. Its peculiarity exists in the method of preparing the charcoal; this affects the color, and results in a brown instead of a black powder. With this powder, experiments with the 6-inch gun give a muzzle velocity of over 2000 feet per second with a projectile of 100 pounds, using charges of 50 pounds, and this result is obtained with less than 15 tons pressure per square inch in the powder chamber. The grain is prismatic, with a central perforation, and as regards its rate of burning, is under complete control in the manufacture; the form provides an increasing surface for the flame during the period of combustion, thus relieving the gun from abnormal pressures at the moment of ignition, but continuing the extreme pressure farther along the bore. The progressive nature of the combustion is very apparent when comparing an unburned grain with others partially consumed, blown out from the gun. [Illustration: COMMON SHELLS, U.S.N.] The gun-carriage, which is a separate study in itself, is carried to a high pitch of perfection, and presents many features being adopted abroad. The importance of a suitable carriage can be appreciated by inspecting the following table, which exhibits the _energy_ that must be controlled by it: Part 1 of 2 +------------------------------------+---------+-----------+---------+ | | | | | | | Weight | Weight | Muzzle | | GUN. | of | of |Velocity.| | | Charge. |Projectile.| | +------------------------------------+---------+-----------+---------+ | | Pounds. | Pounds. | Feet. | | 5-inch steel breech-loading rifle | 30 | 60 | 1915 | | 6-inch steel breech-loading rifle | 50 | 100 | 1915 | | 8-inch steel breech-loading-rifle | 125 | 250 | 2050 | | 10-inch steel breech-loading rifle | 250 | 500 | 2100 | | 12-inch steel breech-loading rifle | 425 | 850 | 2100 | | 14-inch steel breech-loading rifle | 675 | 1350 | 2100 | | 16-inch steel breech-loading rifle | 1000 | 2000 | 2100 | +------------------------------------+---------+-----------+---------+