A most talented and unfortunate man, Sully was born in 1680. He was apprenticed to Charles Gretton, but after training he went to Paris and came under the influence of the great French horologist Le Roy. He established a factory at Versailles, using many London workmen, but this and a further factory at St Germain both failed. Possibly French workmanship benefited greatly from his influence. In later life, he concentrated on marine timekeepers, creating most ingenious work. His work was much supported by Julien Le Roy and he came to be buried in the church of St Sulpice, Paris, in which place he had traced a meridian line on the pavement of the transept, across which a disc of the sun cast a luminous disc, which at noon bisected the meridian.

An obelisk was erected to his memory and the meridian was carried up the face of the monument. Inscriptions on the monument were mostly erased during the revolution which resented that French watchmakers should be indebted to a foreigner.

Image copyright Wikipedia