When firing at a horizontal target, the bullets are not uniformly spread over the whole of the oval of dispersion, those on the nearer side of the minor axis being more crowded together than those on the farther side. Of course the ricochets more or less endanger the omitted spaces, but as these are dependent on the hardness of the ground and on the angles that the strikes make with the actual surface of the ground with which they come in contact, they cannot be relied on. On favorable ground all the bullets will ricochet at all ranges, but the ricochets of those that fall short of the axial bullet will be about the only ones that will be effective. The following rules should be observed: 1. When the object has depth, the fire cannot be too direct. 2. When the object has frontage and little depth, the more oblique the angle of fire is to the front the greater is the area affected. 3. Time-shrapnel is peculiarly adapted to objects moving toward or from the battery. In the first case the fuzes are set rather short, in the second rather long. 4. The best position generally for the point of burst is about six yards above and fifty yards in front of the target. A good rule for the height of burst is the _height of burst in feet = the number of hundred yards in range_. Thus for 1800 yards' range it would be 18 feet (6 yards). 5. The spread may in general be reckoned as ¼ to ⅓ the distance of burst. It must be borne in mind that a variation in the length of burst at any particular range may alter the frontage covered considerably, but it hardly affects at all the depth covered by effective bullets. This depth may be taken as 500 yards for ranges of about 1500 yards, 400 yards for ranges of about 2500 yards, and 300 yards for ranges of about 3300 yards, irrespective of the length of short burst. PERCUSSION-SHRAPNEL. With shrapnel of this kind the cone of dispersion has an ascending angle which will be much greater than the angle of descent, and would vary with the conditions of the ground struck. The velocity is very much impaired by the retardation on graze, and the smallest irregularity may cause the projectile to bury itself, or rise at a very considerable angle. The effect being so greatly inferior to time-shrapnel, they would only be used on particular occasions. CANISTER. Canister is a collection of bullets contained in a can, which is ruptured in a gun by the shock of discharge, the bullets thereby forming a cone of dispersion with its apex at the muzzle of the gun. The can, or envelope, in the U. S. service is known as the Sawyer, and is made of malleable cast iron, weakened by spiral cuts. Canister is essentially a close-quarter projectile for employment against personnel and horses, and under the most favorable circumstances is effective up to nearly 500 yards; up to 300 it is annihilating.