70 On the Rates of Chronometers. [No. 1. 



Wales and Queen ; and the Tudor has fortunately given us an instance 

 which, though without careful enquiry it would at first seem to con- 

 tradict the other two cases, is both explained by that enquiry and offers 

 a good confirmation of the whole theory : the single massive bolt 

 near the Chronometers being probably a vertical magnet, or as a 

 mere mass of iron producing as much mischief as the whole mass of 

 cargo iron at a distance from them in the body of the other ships. 

 But to set the question before the readers of the Journal in all its 

 bearings, we have some farther considerations to take into account ; 

 for " Chronometers are seldom or never found to have the same rate 

 at the end of a voyage that they had at its commencement" says a 

 high authority :* And this indeed is known to every one who has 

 used them. 



I was informed in the course of some enquiries on this subject by 

 Mr. Black, of the firm of Black and Murray, Watch and Chronometer 

 makers of this city, that there is a very general complaint, and indeed 

 that it is almost constantly found, that the London or Liverpool rates 

 given with ships' Chronometers prove incorrect ones on the voyage 

 out ; but that the Calcutta rates found on their being landed here are 

 usually about those determined by the lunars on the voyage, and the 

 whole run from England to the Sand Heads ; (Mr. Black is speaking es- 

 pecially of the Chronometers of the first rate passenger ships and traders 

 to the port, most of which come into his hands for rating, and are 

 watches of the best description ;) and he adds that it is usually found 

 that the Calcutta rate is a perfectly correct one back to England, and 

 even that on the next voyage though a London or Liverpool rate is 

 given with the Chronometer this is usually found incorrect, and many 

 Commanders take up the old Calcutta rate of the last voyage and 

 carry it on, and find it the correct one ! 



This would appear singularly to complicate the problem. Let us 

 see how many conditions are to be taken into account to solve it ; 

 assuming of course that the rate is as carefully determined in London 

 and Liverpool as it is in Calcutta these are 



1. Carrying the Chronometer from the watchmaker's on board 

 the ship ? 



* Capt. Bayfield, R. N. " On Rating Chronometers," Nautical Magazine, 1843, 

 p. 320. 



