Cartier, an Art Deco agate, sapphire and enamel desk timepiece, circa 1920

Cartier, an Art Deco agate, sapphire and enamel desk timepiece, circa 1920, the silvered dial of guilloché design, with black enamel Roman numeral indicators and openwork gold hands, within a bezel applied with light blue enamel with foliate motifs in reserve, to an agate frame of square outline with inverted corners, accented to each corner with a cabochon sapphire, the reverse with a gilt metal strut, dial 4.1cm diameter, frame 7.3 x 7.4cm, dial signed Cartier, back signed Cartier NY and EW&C Co. Inc France, numbered 399