278 INVENtlON OF CriRO:NOMET33R9, &C. 



Cpercerdesrvbis) was proposed in France, during the regency, 

 by M. Fatio, a Genevese, who, not meeting with encouragenent 

 there, came to England, where his secret was received and 

 adopted; and be refers for his authority to H. Sully's Jleg'/tf 

 Artijicielle du Temps ; but I have not found this account in '.ho 

 edition of this book dated 1717» at Paris ; which is the only One 

 to which I have access : the passsage alluded to may probably 

 appear in the edition of 1726, published after the death of tie 

 — and was author, by Julien le Roy. Be this as it will, the art of jewei- 

 Harriso^u &a ^^"S» ^f which Harrison availed himself with judgment, hag 

 been ever since, and continues to be, a material article in the 

 construction of timekeepers. 

 Hpnry Sully The above-mentioned Henry Sully, an Englishman, who 



making time- settled in France in the beginning of the last century, may be 

 pieces for sea. esteemed the first of those great artists who have carried the 

 manufactory of watches to the high degree of perfection, which 

 it still maintains in that country. He laboured, with uncom- 

 mon skill and perseverance, in making timekeepers for sea on a 

 new plan, of which he made a trial at Bordeaux in 1726 ; but, 

 the author dying immediately afterwards, his construction re- 

 ■ mained useless, and has never been copied or improved since 

 that time. Indeed the method, according to which he intended 

 His regulating to effect the isochronism, by means of a lever suspended on a 

 ''n^ bee"^^^*^ thread, or flexible wire passing over curved cheeks, to modify 

 used, and is the vibrations of a vertical balance, though not the same in 

 excep ona e. pj.jj,j.jp|g^ J5 g^ similar in its inconveniencies to Huygens' pei> 

 dulum, that we cannot wonder if it has failed before, nor ex- 

 pect that it will ever be useful for portable machines in future.* 

 Sully made Sully made and published in his works a variety of ideas 



nienfs*Tnd*kr' ^"*^ inquiries ; but the principal practical improvement which 

 particular he he seems to have at first proposed, and has since his lime been 

 frictionrollers frequently employed in timepieces, particularly in France, is 

 the application of rollers to diminish the friction of pivots in 

 timekeepers. 

 John Harrison Before Sully's death, John Harrison had probably made 

 reward of the some progress in his labours for the improvement of time- 



* Sully pubbslicd an explanation of his timekeeper, in a book 

 intituled, Description abregec d' une Horloge de nouvelle Inven- 

 tion, pour la juste mesure du Temps en Mer. 1726. 



pieces, 



