The design of the present clock closely follows the format for that of the rolling ball clocks designed by Sir William Congreve Bt. (1772-1823). Sir William was a colourful gentleman scientist whose principal invention was the Congreve Rocket, a missile used heavily during the Napoleonic wars. Congreve inherited his title in 1814 but was already a fellow of the Royal Society and Member of Parliament. Succeeding his father as comptroller of the Royal Laboratory put him even closer to the attention of the King who it seems took an interest in Congreve's horological inventions. Two of his clocks survive in the Royal Collection both with Congreve's extreme detatched escapement and both signed in combination with John Moxon who appears to have been Congreve's clockmaker.
An almost identical clock signed Robert Roskell of Liverpool and Rio de Janeiro was advertised by Ronald A. Lee, Antiquarian Horology, Vol. six, No. five. December 1969, p. 258