Diagram Telephone Circuit 287 Diagram Radio Circuit 307 The Automatic Pistol, Cal. 45, Model 1911 Facing 316 Receiver, Barrel and Slide Facing 317 Component Parts Facing 318 Component Parts Assembled Facing 319 Ammunition Truck Facing 334 CHAPTER I DEFINITIONS. In the study of any subject which is rather technical in nature, it is absolutely essential that the reader be familiar with the meaning of the words and phrases which must be used in the matter to be discussed. If the subject matter is to be understood there must be a common phraseology. The reader is therefore strongly urged to perfect his knowledge of the following short vocabulary before passing on to the matter which follows. =Ammunition.= A general term applied to all forms of powders, shells, cartridges, primers, etc. (a) _Fixed Ammunition._ When the powder charge is enclosed in a metallic container which is fixed to the projectile, it is called “=Fixed Ammunition=.” (b) _Semi-Fixed Ammunition._ When the charge and metallic container are a fixed unit but are not fastened to the projectile, it is called “=Semi-Fixed Ammunition=.” (c) _Separate Ammunition._ When the powder charge is contained in bags separate from the projectile and containing not a fixed but a varying charge, it is called “=Separate Ammunition=.” =Artillery.= All firearms not carried by hand, excepting machine guns. It is divided into two general classifications: (1) artillery of position, and (2) mobile artillery. (1) Artillery of Position is that which is permanently mounted in fortifications. (2) Mobile Artillery consists of two classes: first, artillery designed to accompany an army in the field; second, railway artillery which requires tracks for its transportation. =Ballistics.= The science of hurling projectiles or of the motion of projectiles in their flight. =Bore.= The hole which extends from the muzzle to the breech. The passageway for the projectile. That part of the tube which is bored out. =Breech.= The rear end of the gun, tube, or barrel. =Caisson.= A two-wheeled vehicle which supports an ammunition chest. The wheeled equipment of a gun section consists of one gun with its limber and one caisson with its limber. For a caisson section it consists of two caissons with their limbers. =Caliber= (=Calibre=). The diameter between the highest points in the bore. =Carriage, gun.= Usually understood to mean all the piece except the tube with its appurtenances and the limber. =Cartridge case.= A hollow cylinder shaped to fit the bore. A container for the propelling charge. =Charge.= (a) _Propelling._ A quantity of powder used in the bore to generate the gases which propel the projectile from the gun. (b) _Bursting._ A quantity of powder used in shrapnel to strip off the head of the projectile and to force out the balls.