72.              $600

Prentiss Clock Improvement Co. “Empire with Calendar”, 1891-1900.  This is not your average calendar clock.  The old oak case is 37 inches long and lifts off the backboard to allow access to the two movements that wind separately – the time movement, which runs 30, 60, or 90 days depending on the springs installed, and the calendar movement that winds on the bottom right when you remove the case cover (it hooks at the top and lifts off).  The calendar spring is huge and, given that it unwinds slightly only once a day, will probably never have to be wound. When you do it will take a large key.  As with other calendar clocks, there is a cam at the top behind the dial that rotates with the hour hand; the first time around it sets itself to trigger the calendar on the subsequent rotation (every 24 hours). As the lever falls off the cam a spring-loaded rod drops and strikes the calendar arm, which releases the calendar to advance the day, month (as appropriate), and date.  Amazingly simple mechanism that seems to work, although the cam and rod need a bit of oil to drop smoothly; the three calendar rollers do advance when triggered.  The time movement is driven by two huge springs that can run for up to 90 days.  I do not know how long this clock will run, but I wound the springs (one arbor winds both) for 64 turns and there was still plenty of spring left.  I quit at that point.  The clock is running easily; there is a long pendulum behind the movement.  The dial is paper and may be original, or a proper replacement; it is signed and slightly worn and yellowed.  The hands appear to be original.  The dial glass is modern, the three calendar windows are likely original, as are the calendar rollers and painted metal date cards.  Schmitt Horan sold two in 2022, for $750 and $1200.  $600-$1200.