~ Cadran solaire diptyque rectangulaire en ivoire à fil-axe, à décor gravé

~ Rectangular ivory diptych sundial with thread-axis, with polychrome engraved decoration, the vertical table presenting a compass rose, the interior decorated with the signs of the zodiac and the latitudes of European cities, the horizontal table with compass comprising three sundials, the dial of the big hours dated "1652", the reverse side presenting a perpetual calendar with brass wheel, monogrammed with the letters "NM" centered with a crown.
Germany, mid 17th century 10.5 x 6.5 x 1.5 cm