During the early 1880's the United States began work on a modern system of seacoast armament. An 8-inch breech-loading rifle was built in 1883, and the disappearing carriage, giving more protection to both gun and crew, was adopted in 1886. Only a few of the weapons were installed by 1898; but fortunately the overwhelming naval superiority of the United States helped bring the War with Spain to a quick close. [Illustration: Figure 15--Ranges.] During this war, United States forces were equipped with a number of British 2.95-inch mountain rifles, which, incidentally, served as late as World War II in the pack artillery of the Philippine Scouts. Within the next few years the antiquated pieces such as the 3-inch wrought-iron rifle, the 4.2-inch Parrott siege gun, converted Rodmans, and the 15-inch Rodman smoothbore were finally pushed out of the picture by new steel guns. There were small-caliber rapid-fire guns of different types, a Hotchkiss 1.65-inch mountain rifle, and Hotchkiss and Gatling machine guns. The basic pieces in field artillery were 3.2- and 3.6-inch guns and a 3.6-inch mortar. Siege artillery included a 5-inch gun, 7-inch howitzers, and mortars. In seacoast batteries were 8-, 10-, 12-, 14-, and 16-inch guns and 12-inch mortars of the primary armament; intermediate rapid-fire guns of 4-, 4.72-, 5-, and 6-inch calibers; and 6- and 15-pounder rapid-fire guns in the secondary armament. The Japanese showed the value of the French system of indirect laying (aiming at a target not visible to the gunner) during the Russo-Japanese War (1904-05). Meanwhile, the French 75-mm. gun of 1897, firing 6,000 yards, made all other field artillery cannon obsolete. In essence, artillery had assumed the modern form. The next changes were wrought by startling advances in motor transport, signal communications, chemical warfare, tanks, aviation, and mass production. GUNPOWDER Black powder was used in all firearms until smokeless and other type propellants were invented in the latter 1800's. "Black" powder (which was sometimes brown) is a mixture of about 75 parts saltpeter (potassium nitrate), 15 parts charcoal, and 10 parts sulphur by weight. It will explode because the mixture contains the necessary amount of oxygen for its own combustion. When it burns, it liberates smoky gases (mainly nitrogen and carbon dioxide) that occupy some 300 times as much space as the powder itself. Early European powder "recipes" called for equal parts of the three ingredients, but gradually the amount of saltpeter was increased until Tartaglia reported the proportions to be 4-1-1. By the late 1700's "common war powder" was made 6-1-1, and not until the next century was the formula refined to the 75-15-10 composition in majority use when the newer propellants arrived on the scene.