A LATE 19TH CENTURY PERPETUAL CALENDAR BLACK MARBLE AND MALACHITE MANTEL CLOCK the gilt lined case with malachite inlaid panels and brass-framed bevelled glass pendulum aperture below a 6" two-piece enamel dial with Roman numerals surrounding a sunken centre with visible Brocot style escapement with jewelled pallets and centre seconds; the two subsidiary dials below for barometer and perpetual calendar fitted a revolving moon phase, days, date, months, and leap year - the eight-day spring-driven movement striking the hours/half hours on a bell with mercury-filled regulation pendulum (51cm high.)