234 



Results of Monthly Observations of [Jan. 27, 



Table I. 

 Magnetic Dip as determined at the Kew Observatory. 





1869. 



1870. 



1871. 



1872. 



1873. 



1874. 



Mean of 

 6 years. 



April 



May 



June 



July 



August . . . 

 September 



o / 



68 2-6 

 0-7 

 0-4 



67 58-9 

 59-2 



68 1-3 



67 57-6 

 57-7 

 55-5 

 56-8 

 590 



68 0-1 



67 59-0 



560 



[67 56-0] 



55-9 



58-1 



67 53-9 



67 53-8 

 53-8 

 53-5 

 530 

 52-3 



67 54-3 



67 53-3 

 50-9 

 51-7 

 51-3 

 51-1 



67 51-6 



67 50-8 

 49 

 47-1 

 50-9 

 49-4 



67 52-2 



67 56-18 

 54-68 

 5403 

 54-49 

 54-85 



67 55-57 





68 0-52 



67 57-78 



67 56-48 



67 53-45 



67 51-65 



67 49-90 



67 54-96 





1869-70. 



1870-71. 



1871-72. 



1872-73. 



1873-74. 



1874-75. 



Mean of 

 6 years. 



October ... 

 November 

 December 

 January . . . 

 February 

 March ... 



68 0-3 



2-3 



0-2 



0-6 



67 59-4 



67 59-0 



68 1-0 



67 58-6 



57-6 



56-4 



57-4 



67 58-1 



67 56-0 

 57-0 

 55-7 

 55-1 

 55-3 



67 555 



O / 



67 54-4 

 55-0 

 53-5 

 53-3 

 53-5 



67 52-8 



67 52-4 

 51-1 

 49-7 

 50-9 

 50-3 



67 50-0 



67 49-1 

 50-0 

 50-3 

 49-2 



48-9 

 67 48-8 



67 55-53 

 55-67 

 54-50 

 54-25 

 54-13 



67 54-03 





68 0-30 



67 58-18 



67 55-77 



67 53-75 



67 50-73 



67 49-38 



67 54-68 





68 0-41 



67 57-98 



67 56-12 



67 53-60 



67 51-19 67 49-64 



67 54-82 



The number within brackets is interpolated. 



The absolute values of the dip correspondiug to the beginning of 

 October in each of the years from 1868 to 1874 and the secular change 

 in each year are as follows : — 



From April 1868 to March 1869. 

 1869 „ 1870. 



1870 

 1871 



1872 

 1873 



1874 



1871 . . 



1872.. 

 1873.. 

 1874.. 

 1875.. 



68 2-13 

 0-41 



67 57-98 

 56-12 

 53-60 

 51-19 

 49-64 



Bee. change. 



-1-72 

 -2-43 

 -1-86 



-2-52 

 -2-41 

 -1-55 



Mean of the six years corresponding "1 ft ^ ? *> qo 

 to middle epoch, April 1, 1872 . . J D/ ° 4 '^* 



Mean secular \ 

 decrease . . J 



2'-15. 



The annual variation and semiannular inequality for the same period 

 are as follows: — 



