ARTILLERY 281 ARTILLERY with the carriages, horses, and stores of all kinds necessary for its effective use; siege artillery is artillery of heavy metal designed to be employed in breaching ling force is gas. This definition of artil- lery excludes the mechanical devices by which, in the days of Archimedes and the Romans, missiles were projected to a considerable distance by mechanical means as the ballista. The discovery of A ROMAN DEVICE FOR SHOOTING FOUR ARROWS AT ONCE fortifications; a train of artillery is a certain number of pieces of cannon mounted on carriages, with all their furniture fit for marching. ROMAN CATAPULT gunpowder in the 13th century made possible the engines of destruction that to-day are the chief reliance of armies. Several crude cannon were used at the battle of Crecy in 1346. They were also employed by the troops that Joan of Arc led to the siege of Orleans. Once the BRITISH 9.2" HOWITZER, MOUNTED ON SEMI-PERMANENT BASE The name artillery is also given to the land troops by whom these arms are served, whether they accompany an army in the field, take part in sieges, or occupy fixed posts. Technically speaking, artillery includes all projectile weapons whose propel- idea was grasped and the possibilities of the new arm demonstrated, developments were rapid. Its use spread through all Europe in the 16th century, but it was not until the 17th that its value in war- fare was measurably utilized by Gus- tavus Adolphus in the Thirty Years'
