JAN-C-178A, JOINT ARMY-NAVY SPECIFICATION, CHARCOAL (FOR USE IN MUNITIONS) (23 OCT 1945) [SUPERSEDED BY S/S BY A-A-59138]., (ARMY NUMBER 50-11-42D AND NAVY NUMBER 51C51A, This specification covers charcoal furnished in the following classes, as specified in the contract or order. Class a., Class b., Class c., Class d.