INVENTION OF CHRONOMETERS, &C, 277 



in Gresham College, where he explained above twenty several 

 ways by which springs might be applied to do the same thing ; 

 and complains of Mr. Oklenbourg, secretary to the Royal 

 Sc/dety, for his conduct and supposed partiality to the Dutch 

 philosopher. Mr. Oldenbourg justified himself against that 

 aqcusation immediately ; but it is worthy of remark, that in 

 his account of the matter laid before the public,* while he men- 

 tions that Dr. Hooke's application of the spring to the balance 

 liad failed repeatedly, and gives several reasons to shew the 

 fliirness of his proceedings, no difference of figure is stated by - 



him to distinguish the manner of applying that principle by the 

 two competitors ; and, as this difference would have prove'd a 

 very strong ground of exculpation to Mr. Oldenbourg, his 

 silence upon the subject affords reason to suppose that it did 

 not exist, and that Dr. Hooke had, before Huygens, actually 

 applied, or shewn the method of applying, the balance spring 

 ill the shape of a spiral. f 



In relating the progress of timepiece making, we must not Advantages of 



omit mentioning the use of precious stones, particularly rubies, Jewelling the 



° . . * ^ "^ ' working parts 



to form the holes m which the pivots of the wheels turn, and of timepieces, 



the pallets upon which the action of the teeth is exercised. 



These jewels, by the high polish given to them, reduce the 



quantity of friction ; and, not being liable to the wear which 



takes place in metal rubbing upon metal, the machine with 



that addition, not only becomes more durable, but acquires % 



<iegree of uniformity in the motion of the pieces, which is very 



favourable to the regularity of its going. 



It does not seem easy to discover, with sufficient certainty. The inventor of, 



the date and author of the application of jewelling to clocks and ^^^f ^^^J^^"*"* ^^ 



watches. F. Berthoud says J that the art of perforating rubies is astribed t» 



ratio. 



* Philosophical Transactions for 1675, No. 118. 



t It is asserted (Supplement to the Encyclopedia Britannica, 

 article watch work, vol. ii p. 785) tliat Dr. Hooke first applied the 

 strai2;ht spring, and then the cylindrical or helical spring, such as 

 has been employed by the late Mr. Arnold, which he afterwards 

 gave up for the flat spiral spring; but I have not been able to dis- 

 cover tlie proof of this statement. 



t Supplement au Traite des Horloges Marines. Introduction, 

 p. viii. note. 



Cpercer 



