532 MILITARY PROJECTILES. 



which they brought into the field. They were usually 

 .made of bars of metal hooped together ; some of very 

 great size are described in books, many of which are 

 now existing in the fortresses of Europe. There is one 

 in Asia, probably the largest in existence. Fourteen 

 feet long, nearly five in diameter, and two and a half 

 bore. 



The form and proportion of a piece of ordnance vary 

 according to the object for which any particular piece 

 is designed. The bore of the cannon is cylindrical ex- 

 cepting a cavity in large pieces, near the breech for the 

 reception of the powder. 



We shall enumerate some of the principal varieties 

 of ordnance, with a short description of the particular 

 purposes of each. 



MODERN ORDNANCE. 



1. The cannon. This name is applied to those pieces 

 whose object is to throw a simple heavy ball, which is 

 to do injury solely by its momentum. It is mounted in 

 various ways, according to the particular purpose for 

 which it is designed, to be placed in a fortress, or in a 

 ship, or to be carried into the field. It is supported by 

 its trunnions, which are two cylindrical projections, one 

 on each side, and is aimed by elevating or depressing its 

 breech by means of wedges, and sometimes by a screw. 

 As has been before remarked, this species of artillery 

 was formerly made immensely large, but experience has 

 taught military men, that by reducing the size more is 

 gained by the ease and the frequency of the discharges, 

 han is lost by diminishing the balls. The size of the 

 pieces has .been consequently much reduced. Those 

 now in use by the European powers throw balls whose 

 weight is from one to fortytwo pounds ; each piece re- 

 ceiving its name from the weight of the ball which it is 

 intended to discharge. 



The balls themselves are generally of cast iron. 

 Stones were formerly used, especially when very large 

 pieces were to be loaded. Stones coated with lead have 

 sometimes been employed. Balls heated in a furnace 



