320 



Rev. S. J. Perry on Magnetic 



[Nov. 16, 





H. F. Dip. 



T. F. 



V. F. 



Winter periods 



3-6321 



3-6336 



6°9 30 8 

 69 31 9 



10-3724 

 10-3843 



9-7152 

 9-7280 





0-0015 



1 1 



0-0119 



0-0128 



Contrary to the results o£ the former paper, these figures show a very 

 large excess in the intensity for the winter months, thus strongly con- 

 firming the conclusion of the increase of the earth's magnetic force with 

 the nearer approach of the sun. The late Kew reductions lead to the 

 same conclusion, but the di:fference for the seasons is not so large. 



Tlie Magnetic Declination. 

 To complete the reduction of the absolute magnetic elements, I will 

 now subjoin a discussion of the Declination observations, although the 

 Dip and Intensity were alone included in the former paper. It has been 

 thought advisable not to apply any correction to the observed Declinations, 

 either for disturbances or for diurnal range, especially as the readings 

 were always taken within a short interval from 9 A.ii. 



Table I. — Monthly mean values of the DecHnation. 



Summer 

 months. 

































Mean 



1870. 



1871 





187^ 





1873. 



1874. 



1875. 



of six 

































years. 





o 





o 







o 







o 







o 





o 









21 



43 13 



21 



42 



9 



21 



21 



55 



21 



20 



42 



21 



3 12 



20 59 



34 



21 21 4« 



May 





38 23 





31 



51 





23 



53 





21 



29 





8 1 



54 



21 



19 40 







47 20 





32 



21 





21 



4 





20 



42 





9 26 



59 



26 



21 43 



July 





39 24 





28 



21 





22 



57 





18 



29 





12 51 



57 



7 



19 52 







43 16 





30 



21 





27 



35 





23 



17 





8 7 



54 



41 



21 13 







39 21 





35 



43 





25 



5 





18 



19 





10 46 



21 



3 



21 S3 





21 



41 50 



21 



33 



28 



21 



23 



45 



21 



20 



30 



21 



8 44 



20 57 



32 



21 20 59 





Winter 

 months. 



1870-71. 



18 



71-72. 



18 



72-73. 



18 



73-74. 



18 



74-75. 



1875-76. 



Mean 

 of six 

































years. 





o 





o 







o 







o 







o 





O 1 





O 1 II 





21 



34 19 



21 



36 



27 





21 



6 



21 



15 



40 



21 



13 4 



21 1 



33 



21 20 22 



November 





41 18 





31 



33 





26 



1 





17 



2 





12 24 



20 53 



9 



20 15 



December 





43 56 





29 



58 





30 



12 





20 



29 





10 41 



48 



59 



20 43 







50 35 





31 



5 





28 



18 





19 



53 





6 28 



53 



14 



21 36 



February 





59 6 





26 



10 





29 



40 





12 



31 





7 45 



54 



26 



21 36 







35 48 





27 



41 





23 



31 





9 



2 





1 47 



52 



39 



15 5 





21 



44 10 



21 



30 



29 



21 



26 



28 



21 



15 



46 



21 



8 42 



20 54 







21 19 56 



■Yearly means... 



21 



43 



21 



31 



59 



21 



25 



7 



21 



18 



8 



21 



8 43 



20 55 



46 



21 20 27 



