In 1866 Reffye, a French inventor, brought out the first mitrailleuse--a mounted machine gun of the Gatling type towing a limber and drawn by four horses. It had 25 rifled barrels and could fire 125 shots per minute. The weapon, however, during the Franco-Prussian War, turned out to be a failure for the reason that it proved an excellent target for the enemy's artillery and was not sufficiently mobile. Accordingly the French government abandoned it. Sir Hiram S. Maxim, who was American born, in 1884 developed a machine gun which operated automatically by utilizing the force of the recoil. This gun was perfected and became a serviceable weapon for the British army in the Boer War. The Maxim gun barrel was cooled by the water-jacket system. When the water became hot it exhausted a jet of steam which could be seen for long distances across the South African veldt, making it a mark for the Boer sharpshooters. This defect was remedied in homemade fashion by carrying the exhaust steam through a hose into a bucket of water where it was condensed. This Maxim gun fired 500 shots a minute. Meanwhile in this country the Gatling gun had been so improved that it became one of our standard weapons in the Spanish-American War. Later on it was used in the Russo-Japanese War. The Colt machine gun also existed in 1898. This was the invention of John M. Browning, whose name has been prominently associated with the development of automatic firearms for the last quarter of a century. In England the Maxim gun was taken up by the Vickers Co., eventually becoming what is known to-day as the Vickers gun. In 1903 or 1904 the American Government bought some Maxim machine guns which were then being manufactured by the Colt Co. at Hartford, Conn. In no war previous to the one concluded in 1918 did the machine gun take a prominent place in the armaments of contending forces. The popularity of the earlier machine guns was retarded by their great weight. Some of them were so heavy that it took several men to lift them. All through the history of the development of machine guns the tendency has been toward lighter weapons, but it was not until the great war that serviceable machine guns were made light enough to give them great effectiveness and popularity. Such intense heat is developed by the rapid fire of a machine gun that unless the barrel can be kept cool the gun will soon refuse to function. The water jacket which keeps the gun cool proved to be the principal handicap to the inventors who were trying to remove weight from the device. The earliest air-cooled guns were generally unsuccessful, since the firing of a few rounds would make the barrel so hot that the cartridges would explode voluntarily in the chamber, thus rendering the weapon unsafe. The Benét-Mercié partly overcame this difficulty by having interchangeable barrels. As soon as one barrel became hot it could be quickly removed and its cool alternate inserted in its place.