OBSERVATIONS FOR TERRESTRIAL MAGNETISM 



fore, somewhat to overlap : nor, indeed, would it be possible in the hours at disposal, 

 to get two separate observations of each element. It would be necessary, in such a 

 case, to observe on two or more days. 



During the course of observations on the "Sealark's" cruise, the declinational 

 element was considered to be of the greatest practical value : and as no more than one 

 day could be given to any set of magnetic observations ; and, further, as it established 

 an equality in the value of the whole results, the observations were made after the 

 sequence tabulated above ; and at the hours stated, as nearly as could be managed. 



It will be noticed that meals had to be interpolated when possible ; and had, 

 indeed, to be " moveable feasts " ! 



Observations for Variation (Declination) Afloat. 



The following is a tabulation of the results obtained during the cruise of the 



Expedition. 



Note. — The variation given at Farquhar Island on the appended Chart was deduced from several 

 bearings taken at anchor, and not from a regular observation from double " Swings " ; and does not 

 therefore appear in this tabulation. 



Magnetic Observations Ashore. 



The following is a general tabulation of the results for Declination, Dip and 

 Horizontal Force, obtained at various positions throughout the cruise of H.M.S. 

 " Sealark." Of the two values given for Horizontal Force, the first is corrected for 

 " P " ; the second is uncorrected, or " X'." 



SECOND SERIES— ZOOLOGY, VOL. XIV 



