R. Lee, The Knibb Family Clockmakers, Byfleet, 1964, pp.36-37, plates 31, 32, 33
D. Roberts, British Longcase Clocks, Atglen, 1990, pp.67, 68, figs.96, 97
J. Darken (ed.), Horological Masterworks: English Seventeenth Century Clocks from Private Collections, Ticehurst, 2003, pp.115, 116
H. van Ende et al, Huygen's Legacy, The Golden Age of the Pendulum Clock, Castletown, 2004, pp.156, 157
A Charles II ebony-veneered month duration Roman striking longcase clock of comparable design is illustrated in P. G. Dawson, The Iden Collection, Woodbridge, 1987, pp.142-143
There are several members of the Knibb family who are recorded as clockmakers, working both in London and Oxford. Joseph was the most famous and inventive of them all. He was the fifth son of Thomas Knibb of Claydon, born in 1640, and apprenticed to his cousin Samuel in 1655. He moved to Oxford in 1662 where he initially met opposition from the freeman traders of the city who referred to him as a 'foreigner'. It was only after three years that this was finally resolved; upon his paying a fine of £6-13-4 and a leather bucket he was granted the Freedom of the City.
In 1670 Joseph Knibb moved to London where it is believed he took over Samuel's workshop. Immediately he was granted the Freedom of the Clockmakers' Company and in 1677 it is recorded that he supplied a turret clock for Windsor Castle and payments were made to him on behalf of King Charles II.
Joseph Knibb was one of the most innovative clockmakers of his time, producing fine clocks with delicate and refined details and experimenting with case materials, dials, escapements and different forms of striking. During his time in Oxford he was involved in the development of the seconds beating pendulum together with his crossbeat and anchor escapements.
THE PRESENT CLOCK
According to R. A. Lee (op.cit.p.115), the present clock is one of only six known examples of three month duration and Roman striking longcase clocks by Knibb, although another movement in a replaced case was sold at Christie's New York, 11 October 2007, lot 4.
The clock movement shows all the refinements one associates with a clock by Joseph Knibb, such as the typical delicate latched pillars and the arched and slender plates. It also employs Knibb's regulation, consisting of a butterfly nut on a sliding square at the top of the suspension spring. This system was used for initial regulation only; fine regulation was achieved by screwing the bob on the threaded rod which was also fitted with a butterfly nut to avoid it being strained.
The brass dial plate having the centre matting extending to the outer edge of the chapter ring and the presence of vacant out-set holes for dial feet indicates it was initially fitted with a skeletonised chapter ring. There are also small vacant locating holes behind the existing spandrels signifying that these have also been changed, most likely at the same time as the chapter ring was replaced. It is known that Joseph Knibb produced dials with extended matting to give his clients the choice of having either a solid or skeletonised chapter ring. It is unclear when this alteration took place but feasibly it could have been undertaken by Joseph Knibb shortly after the clock was finished. Both the chapter ring and spandrels are of the correct style, showing some strong evidence of age and they could be contemporaneous with the clock.
The use of this system is almost entirely restricted to Knibb and was normally employed in his movements of one or three month duration. It did not become widely popular, possibly due to it being rather confusing as the Is are denoted on a small high pitched bell and the Vs in the Roman notation are struck on a larger bell. For example, the hours I-III are struck by three blows on the small bell; IV is indicated by a single blow on the small bell and one on the larger bell; VI is denoted by one blow on the large bell followed by one on the small bell; X uses two blows on the large bell. This system did, however, have a great advantage in power saving when used in long duration movements, as it takes only 30 strokes for twelve hours compared with conventional striking which requires 78. Knibb always used the Roman IV on the chapter ring instead of the usual IIII on his Roman striking clocks.
A Charles II ebony three month duration Roman striking longcase clock by Joseph Knibb of comparable design from The Time Museum, was sold Sotheby's New York, Part V, Part V, Vol.1, 13 October 2004, lot 352.