~ Cadran solaire diptyque rectangulaire en ivoire à fil-axe, la table vert

~ Rectangular ivory diptych sundial with wire-axis, the vertical table presenting a perpetual calendar with brass wheel, the horizontal table with compass, monogrammed on the reverse with the letters "NM" centered with a crown.
Germany, 17th century
7 x 5,5 x 1,2 cm