533 INVENTION Of cnRONOMETERS, SiC. 



^lention of the About the year 1755, according to Count de Bruhl, the lafe 

 detached es- Mr. Thomas Mudge invented a detached escapement, and 

 Mud"e ; con- applied it to a watch which he made for the king of Spain^ 

 irived in 1755, i^grflinand VI. This is the same escapement that was used by 



and different , , _ . , „ . , . , , <• i • i 



from that of the late Josiah Emery in his chronometers, some ot which 



Le Roy. have gone very well. It differs from the constructions which 



w^e have already explained, both in the detent and in the 



communication of the impulse, which in this mechanism takes 



place at every vibration ; but the date will not suffer us to 



consider it as the first invention of the detached escapement. 



The latter es- Our design will not lead us to be more particular respecting 



capementof ^}^q invention of another escapement applied by Mr. INIudge to 



properly ' the chronometers, for which he was rewarded by parliament. 



speaking, de- y^^ g|jj^|| merely observe, that the principle of that escapement 

 tached, but it •' ' ' 



winds up is not free, and it could only be ranked among the detached 



springs, con- escapements, in consequence of giving to that appellation a dif- 

 balance, every ferent sense from the usual meaning attached to the term. The 

 vibration. peculiar mechanism of that machine consists in a kind of dou- 



ble remontoir, which is placed within the escapement, or beyond 

 the whole of the train, and not antecedent to the escape wheel, 

 as in the remontoirs of Huygens and Leibnitz ; consequently 

 the maintaining power of the timekeeper, through the train of 

 wheels, acts only during a short portion of the vibration ; but 

 then the remontoir, or secondary power, which is composed of 

 two springs, by means of their alternate winding and unlocking, 

 is almost in constant action upon the balance. The author 

 himself declared,* that this escapement could not, with propri- 

 ety, be called detached ; and it is rather surprizing, that F. Ber- 

 thoud should,! notwithstanding, have placed it in that class, in 

 the account he has given of it. His opinion of this construc- 

 tion seems, however, well founded ; and we agree with him in 

 thinking, that it is too complex, and requires too nice an execu- 

 tion, ever to become generally useful. , 



* Letters of Mr, Mudge, attached to the Description of his 

 Timekeeper, 1799, p. 152. This escapement is also described in our 

 Journal, quarto series, vol. ii. ; and in the Phil. Trans, for 1794. 



t Histoire de la Mesure du Temps, vol. ii. p. 44. 



la 



