CONSTRUCTION. The body of the bomb is concrete reinforced with steel. (See fig. 69.) Evenly spaced abotu the bods, though staggered, are six cavities, each 13 inches long and 2 1/2 inches wide, housing glass ampoules 10 1/2 inches long and 1 inch in diameter. They are enclosed in a protective wrapping of 1/4 inch thick impure chalk retained in a gummed paper wrapping. The ampoules are retained within their cavities by 1/8 inch thick wood covers, each secured flush with the surface of the bomb body by two screws; the wood protective cover in each case is weakened centrally by a 1/16 deep saw-cut. Each glass ampoule is stated to contain 142 grams of chlorosukphonic acid, containing probably as impurities, small quantities of sulphur and ferrous sulphate; fuming hydrochloric acid is said to be an alternative. On impact the glass ampoule break to re-lease their contents and smoke aries.

The sheet steel tail has four fins.

SUSPENSION. Horizontal by means of an "eye" bolt.

COLOR. Bright green over-all.

Figure 69 – ZC 250-kg Concrete Practice Bomb (Smoke)