Chelsea US Lighthouse Service Clock. A totally original and very late example. The Boston Clock Co. stamped movement has serial number 27800B and the case has serial number 27800. The Chelsea sales ledger shows that the clock was sold to The Superintendent of Lighthouses on July, 1932. A Chelsea Clock Company Certificate of Origin accompanies the clock. This clock is unusual in that it has a nickel plated movement marked Boston Clock Co. which according to Andy Demeter's "Chelsea Clock Company, The First hundred Years" was an affiliate of Chelsea Clock Co. formed on July 14, 1909. The Boston Clock Co. movements and parts were nickel plated as opposed the Chelsea parts which were natural finish or gold plated. The dial, case and hands are all in very fine original condition. The movement has been serviced and keeps excellent time.