Balzola Mechanical Perpetual Calendar

Very rare perpetual calendar whose patent was filed by Polycarpe Balzola on September 20, 1848 with the Prefecture of the Seine. This patent, without state guarantee, was filed "for mechanical provisions of a perpetual calendar". This example, which appears to be the only one known?, is preserved mounted in its original wooden frame, complete and in working order. It is made up of two sheets, each listing six months in six columns (January-June, then July-December) and giving the list of the 365 days of the year. In the center of the frame, a long sheet of paper is wrapped around two wooden rods, one of which pivots, by means of a button located outside the dial, in order to drive the sheet of paper and thus be able to scroll through the years from 1847 to 1936. This calendar therefore gives the dates and days of 90 consecutive years. Perfect original condition of this extremely rare mechanical calendar. Only the sheet for the months of July to August was doubled around its edges. The frame measures 40x29x3 cm.