Copper-alloy and iron barrel lock

Bronze barrel-lock, length of cylinder 3.5 cm. Large cylinder of rolled sheet metal: upper cylinder with engraved zig-zag and transverse grooves figured by Faussett and Roach Smith now missing, though traces of solder which held it in place still survive. In middle of the cylinder, at right angles to vertical plane is a rectangular bronze partition plate, with two drilled holes at the end in which the iron lock bar was inserted. This end still has its bronze cap with the remains of the iron lock bar still rusted into it: straight bar with iron spring, or a split bar whose ends would be pressed together when key inserted to unlock the whole, and would spring apart to lock it when key removed. Spring mechanism operated only in one half of the cylinder: not clear what happened in the other or what the 2 holes for.