Hi, I would very much appreciate any help in identifying the MANUFACTURER / AGE of this presumed French made calendar clock. The clock movement has the serial number, "4892", with NO visible manufacturer marking on the rear plate. The calendar movement has the serial number "1058" and has a presumed manufacturer marking on the rear plate of "C.R" inside a horizontal double oval. The name on the dial is "J. T. MACKAY"; I found a listing for "J. T. Mackay & Son, jewellers" in an 1871-1872 Scottish post office directory, perhaps this was the retailer? On a full wind the clock ran for 15 days; are there 14 day mainsprings or would it most likely be a 30-day mainspring that needs cleaning? Thank you for any information that you can provide.