1877.] 



Magnetic Observations at Kerguelen. 



97 



Tlu Magnetic Intensity. 



The horizontal component of the intensity was determined in the usual 

 way by observations of vibration and deflection. Only one set of obser- 

 vations was taken at a distance from the chief station, viz. that on 

 December 13th, at Swain's Haulover. 



Vibration Observations. 



Station. 



1874-75. 



Tempe- 

 rature. 



Time of 

 one vi- 

 bration. 



Log m X. 



Value of m. 



Observatory Bay . j 

 Swain's Haulover . . . 



Observatory Bay . ^ 



November 13... 



24... 



December 10 ... 



„ 13... 

 Januarv 6 



, 16 



„ 25... 

 February 9 ... 



44-4 

 59-6 

 50-7 

 49-9 

 557 



47- 9 



48- 8 

 58-5 



5-47797 

 5-48405 

 5-48567 

 5'57271 

 5-49071 

 5-48535 

 5-48425 

 5-49062 



0-19703 

 0-19724 

 0-19618 

 0-18250 

 0-19605 

 0-19621 

 0-19650 

 0-19629 



0-45548 

 0-45559 

 0*45476 

 0-45450 

 0-45372 

 0-45527 

 0-45569 

 0-45546 



Deflection Observations. 



Station. 



1874-75. 



Distances 

 of centres 

 of magnets. 



Tempe- 

 rature. 



Observed 

 Deflection. 



Log x . 















November 13... 



ft, 



ro 



38-3 



15 11 50 



9 12003 



Observatory Bay . ^ 



December 10 ... 



1-3 

 1-0 



38-3 

 42-7 



6 52 1 

 15 9 16 



9-11980 

 911920 







1-3 



43-2 



6 51 23 



9-11955 



Swain's Haulover . . . 



13... 



1-0 



44-9 



15 38 14 



913267 







1-3 



45-7 



7 3 39 



913246 



( 

 1 





1-0 



52-2 



15 3 59 



911755 



1-3 



50-0 



6 48 53 



9-11750 



Observatory Bay . •{ 



„ 16 , 



ro 



46-5 



15 10 49 



9-12032 



„ 29 

 Februarv 9 



ro 



41-5 



15 13 



9-12084 



I 



1-0 



51-3 



15 10 41 



9'12060 



In the above Tables m represents the magnetic moment of the vibra- 

 tion-needle, and X the earth's horizontal magnetic intensity. 



In deducing the vertical component and the total intensity from the 

 horizontal force, I have made use of the dip obtained on the same day as 

 the vibrations and deflections, or on the nearest clay possible. As, how- 

 ever, the observation of February 18th is far from reliable, I have adopted 

 for February 9th the mean value of the dip deduced from the December 

 and January observations taken at Observatory Bay, viz. 71° 56' 28". 



VOL. XXVI. 



n 



