1876.] Magnetic Dip fyc. at Kew Observatory. 



Table YI. {continued). 



239 



Month. 



1869-70. 



1870-71. 



1871-72. 



1872-73. 



1873-74. 



1874-75. 



Mean of 

 six years. 



October ... 

 November . 

 December . 

 January . . . 

 February . 

 March ... 



20 27 7-0 

 20 31 48-5 

 20 22 28-0 

 20 24 289 

 20 24 40-8 

 20 29 5-4 



20 20 48-0 

 20 15 25-3 

 20 17 26-2 

 20 17 29-0 

 20 18 5-6 

 20 19 22-6 



20 19 2-4 

 20 9 48-8 

 20 7 5-2 

 20 7 49-1 

 20 8 57-0 

 20 12 6-0 



o 



20 

 20 

 20 

 20 

 20 

 20 



3 38-4 



4 30-2 



1 31-4 



2 25-1 

 4 2-4 

 4 59-9 



19 52 58-7 

 19 49 44-5 

 19 54 0-4 

 19 54 8-0 

 19 51 12-1 

 19 58 47-2 



19 49 35-4 

 19 46 7-9 

 19 41 19-2 

 19 47 54-5 

 19 47 58-9 

 19 46 41-1 



o 

 20 

 20 

 20 

 20 

 20 

 20 



8 51-65 

 6 14-20 

 3 58-40 

 5 42-43 

 5 49-47 

 8 30-37 



1 



20 26 36-43 



20 18 6-12 



20 10 48-08 



20 



3 31-23 



19 53 28-48 



19 46 36-17 



20 



6 31-09 





20 29 2-75 



20 22 6-42 



20 14 6-40 



20 



5 42-39 



19 55 48-46 



19 48 34-11 



20 



9 13-42 



. The absolute values of the Decimation, corresponding to the beginning 

 of October in each of the years comprehended in Table VI., and the 

 secular change in each year are : — 



From April 1869 to March 1870 20 29 



1870 

 1871 



1872 

 1873 

 1874 „ 



2-75 



1871 22 6-42 



1872 14 6-40 



1873 5 42-39 



1874 19 55 48-46 



1875 48 34-11 



Secular change. 



-6 56-33 

 -8 0-02 

 -8 2401 

 -9 53-93 

 -7 14-35 



Mean of the sis years corresponding to "1 9no Q , -, ou.ac) Mean secular "1 

 the middle epoch, April 1, 1872 ] zu y xo ** decrease... J 



-8' 5"-72. 



The semiannual inequality is exhibited in the following Table 



Table VII. 



Date. 



Correction 



for secular 



change. 



20° 9' 13"-42 

 + secular 

 change. 



Observed. 



Mimes calculated. 



April to 



September. 



October to 

 March. 



July 1, 1869 

 Jan. 1, 1870 

 July 1, 1870 

 Jan. 1, 1871 

 July 1, 1871 

 Jan. 1, 1872 

 July 1, 1872 

 Jan. 1, 1873 

 July 1, 1873 

 Jan. 1, 1874 

 July 1, 1874 

 Jan. 1, 1875 



+ 22 15-73 

 + 18 12-87 

 4- 14 1001 

 + 10 7-15 

 + 6 4-29 

 + 2 1-43 



- 2 1-43 



- 6 4-29 



- 10 71 5 



- 14 1001 



- 18 12-87 



- 22 15-73 



20 31 29-15 

 27 26-29 

 23 23-43 

 19 20-57 

 15 17-71 

 11 14-85 

 7 11-99 

 3 9-13 



19 59 6-27 

 55 3-41 

 51 0-55 

 46 5769 



20 3i 29-07 

 26 36-43 

 26 6-72 

 18 6-12 

 17 24-72 

 10 48-08 

 7 53-55 

 3 31-23 



19 58 8-45 

 53 28-48 

 50 32-05 

 46 36-17 



-d d-08 



4-2 43-29 

 + 2 "701 

 4-0 41-66 

 -0 57-82 



- 28-50 



- 49-86 



- 1 14-45 



- 26-77 

 4- 22-10 



- 1 34-93 



- 21-52 



Mean difference between the observed and calculated "I 

 values in the respective semiannual periods / 



4- 40-91 



- 40-90 



TOL. XXIT. 



