IMPROVEMENTS IN CHRONOMETERS. OgC 



superiority of which I leave for your candid readers to de- 

 cide. 



The principle of Mr. Mudge's free escapement (see 4to Mudge's«cap«. 

 Journal, vol. ii, p. 56) is, I believe, allowed to be Ihe beat '°^"^- 

 that was ever offered to the public; but its performance has 

 not been found to be superior to the others, most likelv on 

 account of there being so many pivots and springs, and on 

 account of its tripping, whence it cannot be depended 

 upon. Mr. Arnold says, be has made his penduiuni spring Arnold's. 

 80, that the vibrations are performed in the same time when 

 the main spring is weak, as when it is strong. This per- 

 haps may be in some degree accomplished by very fine 

 workmanship, and a great many trials, but the main spring 

 is not detached from the balance ; and on this account I 

 think the title of being detached is not correct, as the main 

 spring keeps up the action of the balance. 



My alterations and improvements, if I may so call them, Principles of 

 consist, 1st, In reducing the wear and friction of Mr. th8 author's* 

 Mudge's escapement, and putting it into a more simple form. 

 2dly, In applying my equalizing maintaining powers in 

 such a manner, that tension does not alter their strength. 

 3dly, In securing the locking of the tooth against the de- 

 tent. 4thly, In stopping the holes with hard platina. 



For these purposes I have two escapement wheels, equal Description of 

 and similar in all respects, as seen in PI. VI, fig. 1. a A,"" 

 6 B, c C, rf D, e E, / F, represent the teeth of the two 

 wheels, which are so placed, that the tooth A of the upper 

 wheel is exactly between the two teeth a 6 of the lower 

 wheel. These teeth are prevented from revolving round by 

 the two detent pallets G H, which turn on a pin, and con- 

 centric with these detent pallets the pivots of the verge 

 turn, which is in the form of a crank as at M, or more 

 plainly at fig. 2. y y are two joints at the ends of each of 

 the arms of the pallets G H, in which the pieces x x are 

 screwed, so as to allow a free motion. These pieces' are 

 fixed to the ends of two springs K L, which are made simi* 

 lar to the main spring in a gun lock. Each of these springs 

 turns upon a stud m, as seen at K, fig. 3 ; and the spring 

 is made stronger or weaker by the regulating screw w. The 

 stud m is made of brass and the screw is steel, therefore 

 Vol. XX.— July, 1808. Q the 



