322 A V O Y A G E T O 



1779- From this view of the time-keeper it appears, that, for 



Oftober. ^ «• » , , j 



i , 1 near two years, it altered its rate very lnconiiderably, and 



therefore, that its error, according to the Greenwich rate, 

 if we had had no opportunities of correcting it, would have 

 amounted only to 2-+-°. That afterward, at King George's 

 Sound, or Nootka, it was found to have varied exceedingly; 

 of courfe, the longitude, by its Greenwich rate, was be- 

 coming confiderably erroneous. About this time, it mould 

 be remarked, the thermometer was varying from 65 to 41 . 

 The greatefl alteration we ever obferved in the watch was, 

 during the three weeks we were cruizing to the North ; in 

 which interval, it gave the longitude of the Eaft Cape with 

 a difference of twenty-eight miles. I have marked the 

 longitude of Saint Peter and Saint Paul, as given by the 

 time-keeper, notwithftanding it flopped a few days before 

 we arrived there ; this I was enabled to do, from compar- 

 ing the longitude it gave the day before it flopped, with 

 that given by Mr. Baylcy's watch, and allowing for the 

 error of the latter. 



The ufe of fo accurate a mcafurc of time is fufficiently 

 evident, from its furniihing in itfelf the means of approx- 

 imating to the longitude at fea, as may be feen in the above 

 table. But, befides this, we were enabled, by the fame 

 means, to give a degree of accuracy to the lunar obferva- 

 tions, which they cannot otherwife pretend to; and, at the 

 fame time, by reducing a number of thofe obfervations to 

 one time, obtain remits approaching flill nearer the truth. 

 In furveying coafts, and ascertaining the true pofttions of 

 capes and head-lands, it reaches the utmoft. degree of prac- 

 tical exactnefs. On the other hand, it is to be obferved, that 

 lunar obfervations, in their turn, arc abfolutely neccJlary, in 

 order to reap the grcatelt pofliblc advantages from the time- 

 keeper; 



