safety depended therefore on everything being in order and all operations correctly performed.
Fig. 41.—12-in. Gun, Breech Mechanism.
The gun could, however, be fired before the breech was properly secured and a serious accident caused; to prevent this all the movements of modern locks are arranged to be automatic, and wireless electric tubes are used so that immediately the breech mechanism commences to open, the lock itself is moved in the box slide so as to uncover the vent opening. During the first part of this movement a foot on the
