Soon after founding his ormolu manufactory in the late 1760s with his partner John Fothergill, the industrialist Matthew Boulton (d.1799) learnt about the Parisian fashion or 'mode-François' for allegorical clock-cases. In these, sculptural figures serve as allegories, combining mythology and philosophical matters. This Minerva clock is one of the most sophisticated of these allegories. Recalling 'a sacrifice at the altar of Love', the clock movement is incorporated within an urn-capped 'altar' pedestal on a stepped Grecian plinth. The bas-relief medallion within the sacred urn portrays a maiden, emblematic of the virtue of prudence, sacrificing at the altar of Chronos (Time). The urn is unveiled by Minerva, whose owl, emblematic of wisdom and learning, perches discreetly on the pedestal. With her other hand, the laurel-wreathed goddess, whose shield no doubt protects the works of classical authors, indicates the timepiece. Meanwhile a youthful genius, supported by other books, reads from a scroll, sadly now missing, in reverence of the god Chronos, by whose gift all learning and wisdom in the 'useful arts' can be attained. The clock's vase-capped plinth is embellished with festive satyr-masks amongst scrolling Roman foliage.
The inscribed scroll, held by the youthful genius, varied from clock to clock and were quoted in full in James Christie's catalogues. The clock sold in 1778 had lines from Virgil's Aeneid, (XII. 467-9): 'Breve et irreparabile tempus, Omnibus est vita(e); sed famam extendere factis, Hoc virtutis opus'. The 1770 clock quoted the English poet John Gay (1685-1732):'Tis I who measure vital space, And deal out years to human race; By me all useful arts are gain'd. Wealth, learning, wisdom is attain'd: In ev'ry view men ought to mind me, For when once lost they never find me He spoke; the gods no more contest, And his superior gift confest, That Time (when truly understood) Is the most precious earthly good.'.
In 1770, Boulton executed a clock with an 'altar' case, embellished with laurels and bacchic ram-masks, that was designed by Sir William Chambers (d.1796) for King George III (see: N. Goodison, op. cit., pls. 16 and 17). The design of this case clearly inspired that of the plinth that appears beneath the Minerva clock design in Boulton's Pattern Book. This plinth is an enigma; it is not mentioned in either of the surviving Christie's catalogue descriptions and it would have no purpose beneath this clock in its present form. However, it appears from the internal arrangements of this clock that Vulliamy's movement was not fitted while the case was with Boulton and this could explain the absence of the plinth. It is possible that Justin Vulliamy acquired this clock without a movement and fitted one of his own in order to sell it on himself. In 1974, Sir Nicholas Goodison speculated that the plinth illustrated in the Pattern Book design may have been intended as a music box (op. cit., p. 119) but if it was intended only as a space in which a long pendulum could swing, then Vulliamy's movement might not need it and the clock may well never have had it. The movement that Vulliamy fitted uses a short pendulum that needs only the space available inside the existing stepped base in which to swing. This theory is supported by the drum feet and brass underside of the plinth, neither of which are characteristic of Boulton. If Vulliamy bought the case alone, with or without the plinth, and then fitted his own movement, he would then need to replace the underside and the feet.
The model for the Goddess is likely to have been provided by John Bacon (d.1799), sculptor and designer for the applied arts, whose related medallion depicting 'Antonia, mother of Emperor Claudius, beside the urn of Drusus', was acquired by Messrs. Wedgwood and Bentley in 1769 (see T. Clifford, 'John Bacon and Manufacturers', Apollo, October 1985, pp. 288-305).