Second.—Suppose for a particular range the dimension, say height of the 50-per-cent zone, is given in the range table as 4 feet, and we wish to know what percentage of shots will probably strike a zone 7.6 feet high. If we divide 7.6 by 4, we obtain 1.9, and from the table we see that the factor 1.9 corresponds to 80 percentage. Therefore we may assume that 80 per cent of the shots at that particular range will probably strike a zone 7.6 feet high.
For all practical purposes we may consider that the factor of the 80-per-cent zone is 2, of the 95-per-cent zone is 3, and of the 100-per-cent zone is 4.
SHELL.
A shell is a hollow projectile containing a bursting-charge of gunpowder, or some high explosive, and a fuze to ignite the charge at some point of its flight, or on impact. Its penetration into earth at 850 yards may be taken at 12 to 15 feet for field-guns. It is invariably fired with a percussion-fuze, and is used against material.
SHRAPNEL.
A shrapnel consists of a collection of lead balls in an envelope, and bearing a small bursting-charge, which, by action of the fuze, ruptures the envelope at some point of the projectile's flight, and leaves each bullet free to describe its own path, and the paths thus described, taken together, form the cone of dispersion.
Fig. 106.