Zone Energy

A mode of expre ion in artillery, whereby the. relative power of different guns as armor-piercers is estimated, viz: by the number of foot-tons per inch of the shot's circum. ference. At. the. muzzle of each gun, this power is a maximum. Zone, 50 Per Cent.— The space bounded by two parallel lines within which 50 per cent, of the points of impact of all shots fired with the same elevation and azimuth settings will probably lie. The width of the 50 per cent, zone in any direction is equal to twice the probable error in that direction. The area common to the 50 per cent, lateral zone and the 50 per cent, longitudinal zone is the 25 per cent, rectangle. Zone Fire — A fire whose purpose is to overwhelm the area covered with a storm of high explosive shells. It demolishes gun emplacements, destroys communications, blows up ammunition depots and compels the enemy infantry to remain under cover.