16 



SOLAR DIUllNAL A' A 11 1 A T I N 



The summer months comprise April to September, inclusive 

 The Avinter " " October to ]May, 



One scale division equals 0.0000365 parts of the force. 

 Increasing: numbers denote decrease of force. 



1S41-1845 



12" 

 (Noon) 



13 



14 



15 



16 



17 



18 



19 



20 



21 



22 



23" 



+2U" 



July 



797 



788 



782 



780 



779 



783 



788 



7!U 



793 



793 



793 



793 





August . 



820 



811 



803 



802 



804 



809 



815 



816 



817 



816 



816 



815 





September 



844 



834 



829 



828 



828 



832 



834 



834 



832 



834 



832 



832 





October . 



8G6 



860 



856 



854 



854 



854 



854 



854 



855 



853 



853 



852 





November 



861 



858 



853 



852 



851 



853 



851 



851 



852 



852 



853 



853 





December 



894 



889 



885 



880 



878 



878 



879 



880 



882 



884 



884 



883 





.lanuaiy . 



916 



909 



905 



900 



899 



902 



905 



905 



904 



905 



905 



904 





February . 



925 



920 



915 



912 



915 



915 



916 



919 



921 



917 



915 



915 





March 



934 



930 



923 



918 



921 



923 



924 



923 



921 



920 



921 



920 





April 



960 



957 



947 



944 



943 



944 



948 



948 



949 



950 



947 



947 





May 



951 



943 



938 



938 



938 



939 



945 



947 



949 



949 



948 



945 





June 



974 



969 



962 



961 



961 



965 



970 



971 



971 



972 



973 



973 





Year 



895.2 



889.0 



883.2 



880.7 



880.9 



883.1 



885.7 



886.5 



887.2 



887.1 



886.7 



886.0 





Summer . 



891.0 



883.7 



876.8 



875.5 



875.5 



878.7 



883.3 



884.5 



885.2 



885.7 



884.8 



884.2 





Winter . 



899.3 



894.0 



889.5 



886.0 



886.3 



887.5 



888.2 



888.7 



889.2 



888.5 



888.5 



887.8 





Subtracting each value from its respective monthly mean value and converting 

 these differences into parts of the force, Ave obtain the numbers of Table II ; a + 

 sign indicates a greater force than the normal value, a — sign a smaller one. The 

 first three decimals are placed at the head of the table. 



Table II. — Regular Solar-Diurnal Yarlvtion of the Horizontal Force between July, 





1841, AND July, 1845. Values of ^. 







0.000 







0" 



1 



2 



3 



4 



5 



6 



7 1 8 



9 



10 



11" 



-I-21A'" 



January 



. —025 



+085 



+085 



+121 



+194 



+194 



+194 



+231 



+158 



—134 



—353 



—499 





February 



. —005 



+032 



+068 



+105 



+178 



+251 



+324 



+251 



+178 



+032 



—186 



—259 





March 



. +087 



+160 



+233 



+233 



+233 



+306 



+342 



+233 



+050 



—205 



—351 



—534 





April 



. +110 



+146 



+146 



+219 



+292 



+365 



+365 



+292 



000 



—365 



—620 



—657 





May 



. —036 



000 



+073 



+146 



+l46 



+219 



+292 



+073 



—292 



—547 



—511 



—365 





June 



. —056 



—056 



—056 



—056 



+054 



+ 163 



+309 



+090 



—092 



—348 



—457 



—348 





July 



. —017 



+019 



+056 



+092 



+129 



+165 



+202 



+092 



—200 



—455 



-565 



—492 





August 



. +080 



+080 



+080 



+117 



+153 



+226 



+263 



+007 



—358 



—723 



—796 



—540 





Septembei 



. +168 ! +241 



+ 131 



+ I6S 



+277 



+350 



+460 



+131 j —307 



—599 



—708 



—672 





October 



. +116 +262 



+225 



+298 



+335 



+335 



+335 



+189 —030 



—249 



—435 



-395 





November 



000 +035 



+109 



+145 



+181 



+ 254 



+291 



+145 



000 



—220 



—329 



—439 





December 



. —091 +055 



+091 



+128 



+237 



+274 



+347 



+310 



+237 



+091 



—164 



—420 





Year 



. +027 +088 



+ 103 



+143 



+201 



+259 



+310+171 



—055 



—310 



—456 —469 





Summer 



. +043 +072 



+072 



+116 



+174 



+247 +317 l+llt; 



—209 



—505 



—610 1 —512 





Winter 



. +014 +105 



+134 



+171 



+226 



+269 +305 \ +225 : +098 



—114 



—303 —424 





