RATES OF CHRONOMETERS. 



21 



standard ; the rates, which are given for each chronometer to the 

 closest figure deemed necessary, being arranged in vertical columns, all 

 discrepancies are easily seen, and show the reliance that is to be 

 placed on their performance, and in our determination of longitudes 

 through them. 



By referring to the numbers in Chapter I, it will be seen by whom 

 the instruments were made, and which have performed the best. 



After such proofs, it might seem invidious were I to designate any 

 particular instruments ; yet I cannot deny, that greater confidence was 

 felt in some, when navigating through the devious routes followed 

 during the course of the Expedition, than in others. I must give the 

 assurance, however, that all the chronometers were uniformly at- 

 tended to with great care. 



In the tables, I am aware that many discrepancies appear that can- 

 not well be imputed to the instruments themselves ; these may possi- 

 bly have arisen with ourselves, but it is now beyond my power to de- 

 termine : such the record books give, and they must stand. All those 

 who are conversant with the use of chronometers well know the lia- 

 bility of error of a few seconds in the comparisons, and will make 

 allowance therefore in places in which it is apparent that such may 

 have been the case. 



As the Table of Rates fully explains itself, I deem it unnecessary to 

 offer any further explanatory remarks. It shows the changes and 

 transfers of the chronometers, and their periods of absence from the 

 ships; when they were returned, the comparisons and rates were 

 again taken up, as before. 



The capital letter of the name of the vessel on board of which the 

 chronometer was, is placed over the head of the column, and when 

 transferred to other vessels, is then noted in the column of remarks. 



It is necessary to remark here, in reference to the Peacock's instru- 

 ments, that the daily record of comparisons, for a part of her cruise, 

 was lost at the time of her wreck ; but I have endeavored to supply 

 this, by the weekly and monthly returns which Captain Hudson made 

 of their performance during the period. 



c 



