1851 Great Exhibition: Official Catalogue: Class X.: A. Watkins
From Graces Guide
85A. WATKINS, A., 7 Weymouth Terrace, City Road — Inventor and Manufacturer.
Original eight-day chronometer, striking the hours; being a self-acting repeater, chiming the quarters upon a set of five bells, and showing the day of the month; each set of works detached; the whole comprising 200 pieces of mechanism in a diameter of not more than two inches.
Chronometers of three-quarter plate construction, with hard cylindrical springs, jewelled with rubies in every hole; presumed to be the smallest ever made of the same construction, the diameter being nearly that of a guinea.