Description of the deflection board (model of 1906) with De Carre drift chart for 12-inch mortar : mechanical features, rules governing its care, operation and preservation in service, April 4, 1907, revised December 13, 1907.
Title
Description of the deflection board (model of 1906) with De Carre drift chart for 12-inch mortar : mechanical features, rules governing its care, operation and preservation in service, April 4, 1907, revised December 13, 1907.