DIFFERENCES IN THE MAGNETIC NEEDLEi JQ5 



and eaft coafts of New Holland, I always endeavoured (o take 

 the angles on fliore with a Troughton's portable theodolite, 

 and to obferve for the variation in the fame places, that all the 

 errors might be done awaj or correded ; and as I was fre- 

 quently fortunate enough to carry on my furveys in this manner 

 for weeks together, inftances that might corroborate or contra- 

 didtheprecedingremarksareneither very numerous'or pointed; 

 the following are the moft remarkable : 



April 1 5th, AM? IT weftern part - - N 15" fc 



11" 50' i A peaked hummock - - N 20 E 



— Furthcft extreme from deck - S 54 E 



— Centre of a naked fandy patch - E 0^ S. 



In the fame manner upon fingle fets of bearings I was obliged to 

 allow a variation different from what I fuppofed the true to be, unlefs 

 the fliip's head was nearly north or fouth : but, that I might pro- 

 ceed as little upon conjefture as poffible, I always endeavoured to 

 get obfervations for the variation when the fhip's head was in the 

 fame direftion as when I had taken or wiflied to take a particular 

 fet of bearings, and I then allowed that variation exactly, what- 

 ever it was. The perplexity arifingfrom difagreements in bearings 

 wasbythefe means much alleviated, and happy agreements were 

 frequently produced, when, without fuch corre6|ions, there was 

 nothing but difcord. 



TABLE 



