io8 APPEND! X. 



Observations on the Variation. 



^ I '^ H E Variation of the compafs, always an interefiing 

 object to navigators and philolophers, became pecu- 

 liarly fo in this voyage from the near approach to the 

 Pole. Many of the theories that had been propofed on 

 this fubjeft, were to be brought to the tefl: of obferva- 

 tions made in high latitudes, by which alone their 

 fallacy or utility could be difcovered. Theyofcourfe 

 engaged much of my attention, and gave me the fulleft 

 opportunity of experiencing, with regret, the many im- 

 perfedions of what is called the Azimuth compafs. This 

 inftrument, though fufficiently accurate to enable us to 

 obferve the variations fo as to fteer the fhip without any 

 material error, with the precaution of always ufing the 

 iame compafs by which they are taken, is far from being 

 of fuch a conftrudion as to give the variation with that 

 degree of precifion, which fhould attend experiments on 

 which a theory is to be founded, or by which it is to be 

 tried. The obfervations taken in this voyage will fully 

 evince this, by their great variations from one another in 

 very fhort intervals of time ; nor is this difagreement of 

 fuccefiive obfervations peculiar to the higher latitudes, 

 and to be imputed to a near approach to the Pole, as I 

 found it to take place even upon the Englifh coaft. 



As to the obfervations themfelves, they were taken 

 with the greateft care, and the moft fcrupulous attention 



to 



