Breguet ARINE ÉQUATION MARCHANTE 5887 Manual De Instrucciones página 26

2. Temporary date setting
E pushbutton III
English
Pushbutton III simultaneously adjusts the date C, as well as the
day of the week D and the equation of time disk.
Use pushbutton III to temporarily adjust the date C on the first
day of the month.
In this example, the date is adjusted to Tuesday 1 April.