The internal mirror is mounted on a pivot. The angle can be controlled by the elaborate wingnuts on either side. The box is 10.5x10.5cm.
The mirror is backed by this page from an old French almanac: a small book that had a calender of an entire year with the saints for every day; in this case the months July, August and September. Who the saint was for a specific day varied in time and country. The almanac also contained the dates for markets, and the departure time of ferries and coaches. Often the time for seeding and harvest was connected with a certain saint. The number in between is the date of the month, the letter behind stands for saint (S=saint, ste= sainte (female)).

In Holland there is still an almanac for sale made for every new year, it is called: the Enkhuizer almanac.

Thanks to Bert Degenaar and especially Pieter de Ruiter for this excellent description.

Dating this page is a bit difficult, but this site helps. Given that France switched to the Gregorian Calendar between 1582 and 1682, the years that July 1 fell on a Tuesday (mardi) are: 1710, 1721, 1727, 1732, 1738, 1749, 1755, 1760, and 1766 (in the context of this microscope). So, when one compares this scope to other dated box microscopes, it is possible that its year of manufacture was either 1727, 1732, or 1738. The focusing mechanism and simple construction suggest an earlier date, so possibly this instrument was made in 1727.