J. Evans, Thomas Tompion at the Dial and Three Crowns, Ticehurst, 2006 R.W. Symonds, Thomas Tompion, His Life and Work, London, 1951, pp.145-148 and pp.192-194
Tompion No.8 dates from the first year of Tompion's numbering system, which Jeremy Evans has suggested started circa 1682 (p.71). The 'Phase I' design was first used on his un-numbered clocks, commencing some five or so years before. Stylistically it bears many features in common with other examples (see Symonds pp.145-148), particularly with regard to its case. The back plate engraving and signature reserve may also be considered typical of early Tompion. Interestingly, however, it has a narrower movement, with plates joined by five pillars rather than the more customary seven. These are features it shares with Tompion 38 (see Antiquarian Horology, Volume fifteen, September 1984, G.E. Marsh advertisment), along with having a date aperture and a strike/not silent lever above XII on the dial. Why these two clocks should have narrower movements must remain a matter of conjecture. As Jeremy Evans writes: '[R]eally we know very little about Tompion's production arrangements, and to illustrate this it only needs to be pointed out that close examination of the three principal types of watch retailed...strongly suggests that they were being made in different workshops, by different teams of craftsmen'.