Flying pig A large projectile from a type of mortar used by the Germans. Could be seen in flight and because of appearance and size were nicknamed "flying pigs." Fokker German plane. Very fast, good climber. G.H.Q. Great Headquarters. G 2 Intelligence Department of Great Headquarters. Great Headquarters was divided into several groups, designated, for convenience, by lettered numerals, such as G 1, G 2 and G 3, etc. G.I. cans A large shell. Because of size and usual coat of grey paint, soldiers declared they resembled the galvanized iron cans used for garbage. Hence, G.I. Can. G.O. General Order. Hedge hopping Another name for contour chasing. Flying dangerously low and zooming over obstacles. High-tail A plane, when at highest speed possible straight ahead, carries its tail high. To high-tail means to go at highest rate of speed. Immelmann A sudden turn, reversing the direction. First used by a German aviator, Immelmann, and later used by all air pilots. Intelligence That section of Great Headquarters devoted to the handling of all spies and the collection of information concerning the enemy. The activities of the department are too great to be outlined in a brief definition. Liaison Contact, communication with. When several units are operating in unison, each dependent upon the other, the contact and coordination is called liaison--a French word. Limey Nickname for a British soldier. Looie A Lieutenant. Observation balloon A captive balloon, of sausage shape, carrying an observer whose duty it is to spot artillery fire, etc. The balloon is paid out on a cable attached to a winch. Such balloons are always given protecting ground batteries to ward off enemy planes. Observation bus Generally a two seated plane, carrying pilot and observer. Slower than pursuit planes, but more heavily armed. O.D. Olive drab; color of uniform. Old Man Captain, Major or Colonel. Usually applied to commander of the Units.