157 



TABLE IV. Observations of the Magnetic Dip, at the Kew Observatory, hi 

 1860, with 9- and 6-inch Circles (Robinson's and Barrow's), without Verniers. 





The observations were all made in the plane of the magnetic meridian. 



The values obtained for the Dip at the epochs of 1821 and 1854, 

 having been derived from observations made at the close of August 

 and beginning of September in those years, require a small cor- 

 rection for annual variation, to bring them into strict comparison 

 with the values at the two other epochs of 1838 and 1859, which 

 have been derived from observations distributed generally throughout 

 the years. A correction of +0''5 has been applied to each on this 

 account. 



Corrected Dip at the several Epochs. We have then the observed 

 Dips, finally corrected, at the several epochs as follows : 



1821.65 70 03-4 N (1) 



(2) 



(3) 



(4) 



1838.3 '.. 69 17-3 



1854.65 68 31-6 



1859.5 . ..68 21-5 



VOL. XI. 



