Chronometers. 303 



rpmarks on the origin of those trials, and on the favorable effect 

 which they have had on the art of chronometer making, may not 

 inappropriately close our observations. 



Notwithstanding the encom'agement which Goverment had long 

 afforded to the art, by purchasing chronometers largely, and at liber- 

 al prices, for the use of the navy, and the very considerable rewards 

 which had been given to three of the leading artists (3000/. each) for 

 improvements which they had introduced in the construction of the 

 instruments, yet the general state of the art was much below what 

 was generally believed, and might have been expected. 



Aware of this fact, and desirous that the art which we exercised 

 should participate in the general improvement, we, in 1818, addressed 

 a letter to J. W. Croker, Esq., at that time Secretary to the Admi- 

 ralty, respectfully suggesting that Goverment might further and 

 more essentially aid the progress of the art, by giving frequent and 

 small rewards to ingenious workmen who made instruments that ac- 

 tually performed well, without reference to the principles on which 

 they were constructed. 



The public trials at the Royal Observatory commenced in 1820, 

 and the performance of the chronometers on the first trial proved the 

 correctness of the opinion which we had formed as to the general 

 state of the art of chronometer making. The prizes of 3007. and 

 200Z. were that year adjudged to chronometers which Goverment 

 would not at the present time purchase at any price. 



Several of the chronometers which we sent on trial in the various 

 scientific expeditions to the Polar Seas and towards the Equator, 

 having performed satisfactorily, we sent some of our experimental 

 chronometers to Greenwich on trial, a few years after the public 

 trials were first established, and the opportunity thus afforded us of 

 having the effect of our successive alterations tested by daily obser- 

 vation, enabled us to discover and correct many minute sources of 

 error, which we should otherwise most probably never have discov- 

 ered. 



The opportunity, too, of returning for trial chronometers which, 

 having performed satisfactorily and which we had endeavored to 

 improve gradually led us to the discovery of the principle which en- 

 ables us now to control at pleasure, and to counteract, any general 

 tendency in chronometers to deviate from their rates. 

 We are, Sir John, yours, respectfully, 



Parkinson and Frodsham. 



