chapitre "Des lumières aux Républiques" - Lot 148

chapitre "Des lumières aux Républiques" Mastery lock with four secrets and its key Lock: 10, 2 x 20, 4 cm - key: 12, 62 cm. NB: Described by Duhamel Dumonceau in 1767, in "L'art du serrurier", page 194, plate 26, the locks of mastery impose a secret to open. This one has four more complications. To the right of the normal keyway, a second keyway offset by an eighth of a turn is partially obstructed by a spring-loaded lever whose knob is to the left of the keyway. A right turn of the key followed by a quarter turn to the right opens the center latch and the left trigger. To release the right-hand trigger, the key is turned one-eighth of a turn to the left. Its bit is then aligned with the second keyway, which is actually an exit. You then pull the key towards you, partially pulling it out. But to do this, you have to push the lever knob to the right to free the key exit from its obstruction. It takes two hands to finish the opening: (1) the left hand moves the key exit shutter while (2) the right hand pulls the key and (3), keeping it semi-extracted (4), turns the key an eighth of a turn to the left and finally the left hand lifts the hinged trunk lid. While the triggers of these locks swing sideways to open, the right trigger of this lock swings back and forth perpendicularly.