Cedric Jagger, Royal Clocks, Hale, 1983, pp.101-103, figs.140-143; H. Alan Lloyd, Some Outstanding Clocks over Seven Hundred Years 1250-1950, Antique Collectors' Club 1981, pp.292-293, pls.132, 133; C. Gilbert, Thomas Chippendale, London, 1978, figs.35-7; Derek Roberts, English Precision Pendulum Clocks, Schiffer, 2003, p.204, figs.21-6A,B,C; Clutton and Daniels, Clocks and Watches in the Company of the Worshipful Company of Clockmakers, Sotheby Parke Bernet 1975, p.87; Richard CR Barder, The Georgian Bracket Clock 1714-1830, Antique Collectors' Club 1993, pp.139 & 147-149.
John Grant (1781-1810) was an exceptional clockmaker, described by Cedric Jagger as 'one of the finest of the London clockmakers at the end of the 18th Century'. He was apprenticed to his uncle, Alexander Cumming (1733-1814), and it is possible they may have been in business together at some point (see Jagger p.101). Certainly Cumming's influence can be see in the case design of the present clock.
The case is reminiscent of the George III 'antique' manner of the 1770s. The classic design, with its panels framed with hollowed 'French' corners is typical of the work of Thomas Chippendale (d.1778), author of The Gentleman and Cabinet Maker's Directory (1754-1763). The evolution of the case design can be traced back to Alexander Cumming's masterpiece, the barograph clock made for George III circa 1765, under the direction of the architect Sir William Chambers. In particular it references Cumming's second barograph clock, housed in Chippendale's marquetry and ormolu-enriched case and made in the 1770s.
Comparison may also be made with a John Grant month-duration spring-driven regulator in the museum of the Clockmakers' Company at the Guildhall, with which it shares some design elements. That clock also has glazed front door and side panels and the design of the plinth, particularly the panel with hollowed out corners, is very similar to that of the present clock. The trunk pilasters appear to be identical and indeed in both instances these hark back to Alexander Cumming's barograph clock of circa 1770. The hood section of the case also references the 'balloon' bracket clocks of the 1790s/early 1800s. The white enamel dial, sometimes with crossed minute track as on Grant's clock, was a fashionable accompaniment to the balloon case. See, for example, Barder (p.139). Grant appears to have had a taste for the 'antique' manner. A small table clock by him, with carved volutes to the sides in the neo-Grec style and also with white enamel dial can be seen in Barder (p.190).