According to the records of Montres Breguet, the present watch was sold on 4 June 1927 to Mr. Louis Harrison Dulles for the amount of 6,700 Francs.
The "wandering hour" dial first appeared in the 17th century. In the 1920s and 1930s Breguet sold wandering hour watches with a system patented by the Swiss watchmaker Robert Cart around 1925 (see lot 298).
The expression "Chronoscope" is taken from the Greek "chronos" for time and "scope" for range, sector and stands for an instrument for accurate measurements of small intervals of time.
A similar watch is illustrated in Breguet - Watchmakers since 1775 by Emmanuel Breguet, p. 316.