This is a remarkable survivor — a French pocket notebook with a perpetual calendar in the cover, published in the late 1830s. Movable parts in books of this age are rare, and the few that survive, such as volvelles, tend to be inside the book. This is the first example I've had where the moving parts are in the cover and are designed for daily use. Given the fragility and ephemeral nature of items like this, it's unlikely that many lasted longer than a few years. In this case I suspect that the paper strips were stored folded within the leaves for a long time, keeping them safe.
The perpetual calendar is adjusted by moving two paper strips, one printed with the days of the week and the other with the names of the months (and number of days they contain). Inside are twenty pages for the owner to fill. Four are made from a stiff, probably waxed, material that could be easily cleaned and reused by applying a damp cloth.
The notebook was probably a promotional item for a merchant, as the back cover includes a list of clothing and household items that they presumably sold.
This book's owner filled it with notes dated 1838, 1839 and 1840, mainly personal and household accounts, with prices paid for items such as butter, cakes, liquorice pats, a small bottle of phosphoric acid, a skein of black thread, a small round mirror, an almanac, and even a book on astrology.
On the inside rear cover someone, possibly a child, has sketched what appears to be a French naval officer and written out the Jesuit motto “ad majuum dei gloriam” — “To the greater Glory of God”.