shooting large caliber shells at the same instant, the firing being produced by an electrical current that set the guns off thus producing a power ful concentration on their target.
The adoption of gas made necessary the addition of new units to the army organization. A Chemical Warfare Service was made an important branch of the American and other armies. Its functions consisted in the "operation and maintaining or supervising the operation and maintaining of all plants engaged in the investigation, manufacture or pro duction of toxic gases and proving grounds used in connection therewith, gas defense appliances, the filling of gas shells, and the necesary research con nected with gas warfare." The organi zation provided for various units, each with its special work. The most im portant of these were the Gas Defense Production, which supervised the making of gas masks; the Gas Offense Produc tion, which concerned itself with the making of gas for the purpose of attack; and the Training Section, which taught to officers and men the approved methods of gas warfare.
On the battle fronts the utmost care was taken by means of signs and sounds to protect the troops. Sirens, horns, and bells were sounded to warn of an im pending attack. Signs were posted bear ing the legend "Gas Alert On" and "Gas Alert Off," the former meaning that the ground was dangerous and that masks must be carried in front for instant use, while the latter permitted less caution. Special training was given in rapidity of adjustment, and the regulations required that the mask be put on in six seconds or less. The mask itself became more effective, especially in the case of the American mask by the use of "soda lime" produced by a secret process. Constant drill and warning proved so effectual that the casualties were greatly diminished, and toward the end of the war it be came almost a maxim that a soldier who was "gassed" owed his misfortune to his own carelessness. See WORLD WAR.