On ascertaining t?ie Rates of Chronometers by Signal. 161 



16. Prince's Street, has stated to me, that he could, with per- 

 fect ease, adapt the Observatory clock, or any other time-piece, 

 so as to disengage the ball at a given hour, without injury to the 

 time-piece, which would certainly be a very great convenience. 

 I am, &c. Rt. Wauchope. 



To Professor Jameson. 



The great importance of the chronometer, and the additional 

 security and precision which it has imparted to the science of 

 navigation, need not here be insisted upon. It is deeply to be 

 regretted, however, that a discovery only second to the mariner's 

 compass and quadrant, should still be so limited in its use 

 among the merchant ships of this and other countries. Nor is 

 the cause of this limitation (which is producing annually so 

 much waste of life and property) difficult to be accounted for. 



The obvious and acknowledged reason why merchant ships 

 do not carry time-pieces so frequently as they otherwise would, 

 is not so much owing to the expense of the instruments, as to 

 the difficulty of obtaining a good rate, arising from the inabili- 

 ty of masters of ships to obtain one, both from the great accu- 

 racy required, and the want of time and opportunity. This 

 last cause applies to men-of-war equally with merchant ships, 

 as it may, and does frequently occur, that ships come to an 

 anchor even upon our own coasts, without having it in their 

 power to get a set of observations for an artificial horizon. 



It is a custom, I believe, pretty generally on board of King's 

 ships (when a good opportunity offers) to send the time-pieces 

 on shore for the purpose of getting a rate, which they do with 

 considerable risk to the chronometer ; and, after all, it is fre- 

 quently found, that the shore rate and ship rate do not agree, — 

 the cause of this disagreement arising from the same source of 

 error to which compasses are subject, viz. the magnetic influence 

 which the mass of iron in the ship has upon the instrument. 



Many advantages would therefore accrue, could an accurate 

 rate be found without moving the time-piece out of the posi- 

 tion or PLACE in which it is to remain whilst at sea, and with- 

 out the necessity of sending on shore to obtain one. 



The plan I have to recommend for obviating all these diffi- 

 culties, is as follows : — Suppose, at Portsmouth for instance, it 

 was notified to all the ships at Spithead and St Helens, to mer- 



OCTOKER — DECEMBER 1829- ^ 



