The makers, Dobbie McInnes Co. traces their roots back to the beginning of the 20th century when shipbuilding on the river Clyde was thriving. They were appointed as ‘Instrument Makers and contractors to the British Admiralty’ producing accurate chronometers to calculate longitudes. Serial No 9602.

See http://www.mhs.ox.ac.uk/database/brief.htm?Invno=44156&NumberOfImage=1