360 ON THE ERRORS OF CHRONOMETERS, ARISING 



effectually as could be desired, As the balances are now ge- 

 nerally, I believe, wrought out of a solid piece of soft steel, en- 

 compassed by a rim of brass, it would conduce to the same 

 end if they could be turned in the plane of the magnetic equa- 

 tor ; and still further, when blued after polishing, if this pro- 

 cess were completed while the balances maintained the same 

 position. 



But as a balance that has been freed from magnetism might 

 again acquire polarity, the third method I have to suggest 

 might probably prove the most efficacious, as regards steel- 

 balances and balance-springs, and it has the advantage of be- 

 ing applicable to all small chronometers. As its employment, 

 however, would be attended with some difficulties, I merely 

 throw out the hint at present, but with the hope of being en- 

 abled hereafter to determine the efficacy of the plan by expe- 

 riment. 



A chronometer, even with a magnetic balance, may keep 

 very accurate time when on shore, and yet perform very ill at 

 sea. Because, while on shore, its position is usually preserved 

 unchanged : it is perhaps kept on a shelf or a bench j in either 

 case it is not liable to be turned from its position, since the 

 lock of the box being commonly kept in front, naturally fixes 

 it invariably in the same way. But when the same chrono- 

 meter is taken to sea, its position is changed at the least every 

 time the course of the ship is altered ; and with every change 

 of position there is probably an alteration of rate. Whenever 

 the north pole of the balance is directed towards the north, 

 the rate will (it is presumed from the experiments of Mr Var- 

 ley) be accelerated; when towards the south, retarded. 

 Could, however, any method be adopted for giving a uniform 

 position to the chronometer, the errors arising 1 from the above- 

 mentioned cause would no doubt cease. Something might be 



done, 



