Very rare Swiss calendar with Pouzat variation escapement

A large and very rare, late 18th century Pouzait lever escapement watch, in a gold case, with calendar dial.

MOVEMENT : Variation on a Pouzait lever escapement, possibly by Vincent Martin, an apprentice of Ferdinand Berthould.

REFERENCE : La Montre Francaise by Adolphe Chapiro – see Fig. 431.