l62 OF PROJECTILES.

138. There may be some defects so slight as not to meritattention; while there are others that must be prejudicial,according to their nature and extent; as the eccentricity of thebore, the number, depth and situation of the flaws or cavi-ties, the wrong position of the vent, or a failure in otherpoints previouily concerted with the contractor. As, on theone hand, nothing should induce officers to receive gunsthat cannot be depended on ; so, on the other, they shouldnot be over scrupulous in their examination, lest the foun-ders under pretence of the minute strictness of the scrutinyenhance their price.

139. Iron guns should be subjected to the same proof andexamination: but as the hardness of the metal is ascertained,there will be no reason to apprehend any orbicular cavitiesbeing formed in the charging cylinder, or any impressionsmade by the shot in the bore. If properly cast of metal of agood quality, they may be proved with iron shot withoutfear of damaging or hurting them ; the quantity of powdershould be determined by the thickness of metal, agreeably tothe rules laid down in the 6 th chapter.

140. The same precautions and care should be taken inproving and examining mortars : hut any little hollows orflaws in the chafe may be disregarded, unless from their num-ber and proximity, there be reason to apprehend an essentialdefect in the interior of the metal.

SECOND PART.

Of Projectiles.

141.Tr PIE RE are two general methods of annoying'an enemy: with missile weapons ; or with pointed and cut-ting instruments. Under the first head, the ancients madeuse of the balista and catapult#, for throwing large stones andarrows to great distances; and of Jlings and bows for throw,ing them to shorter distances.

The