Range of Atmospheric Temperature. 



579 



the sun, it will of course be least in winter and greatest in summer. A 

 given increase of the range in winter \^ill thus denote a greater relative 

 increase in the power of the sun than the same absolute increase of range 

 m summer. Thus if the sun's influence were doubled, the range for De- 

 cember (Table I.) might be supposed to rise from9°-17 to 18°-34, and the 

 range for July from 18°-49 to 36°- 98. In fine, what we have to do in 

 order, according to this hypothesis, to obtain the apparent increase in 

 solar activity is to find in what proportion the normal monthly range is 

 increased. This is done in Table II., in which the normal range for each 

 month is reckoned = 100. But here we must bear in mind that while 

 Table II. is constructed in conformity with a certain hypothesis regard- 

 ing the solar action, it does not necessarily follow that this hypothesis is 

 correct ; indeed Table II. is only to be regarded as exhibiting a different 

 way of arranging the results. 



Table II. — Exhibiting the Proportional Solar Activity, the Kormal for 

 each Month being reckoned =100. 



Year. 



1 



1 Jan. 



Eeb. 



1 



Mar, 



Apr. 



May. j June 



1 



! July. 



Aug. 



j Sept. 



i 



Oct. 



1 



]N"OY. 



1 



Dec. 



Mean of 

 the year. 



1855. 



76 



91 



94 



106 



93 



93 



86 



94 



105 



83 



73 



96 



90-8 



1856. 



81 



77 



82 



92 



76 



95 



93 



99 



96 



91 



92 



IC9 



90*2 



1857. 



84 



129 



96 



83 



1 04 



119 



IC4 



102 



93 



94 



81 



97 



98-8 



1858. 



123 



92 



J15 



98 



97 



112 



95 



109 



95 



103 



IC2 



102 



103-6 



1859. 



103 



121 



97 



97 



97 



96 



114 



107 



98 



97 



114 



114 



104' 6 



i860. 



112 



116 



92 



94 



lOI 



73 



85 



74 



95 



90 



87 



102 



93'4 



1861. 



III 



108 



97 



lOI 



97 



85 



82 



103 



103 



97 



122 



no 



101-3 



1862. 



100 



72 



83 



78 



88 



85 



86 



90 



,93 



95 



102 



105 



897 



1863. 



107 



122 



124 



106 



100 



93 



116 



96 



100 



88 



104 



114 



105-8 



1864. 



lOI 



98 



113 



103 



lOI 



97 



112 



118 



98 



88 



121 



100 



104-2 



1865. 



102 



95 



87 



133 



108 



109 



100 



97 



129 



113 



113 



82 



105-7 



1866. 



106 



105 



92 



88 



104 



104 



95 



92 



77 



91 



I 12 



117 



98-6 



1867. 



122 



96 



86 



88 



lOI 



103 



96 



102 



lOI 



112 



no 



1 10 



102*2 



1868. 



92 



123 



III 



97 



116 



123 



121 



95 



120 



119 



95 



97 



109-1 



1869. 



109 



lOI 



84 



109 



86 



lOI 



114 



107 



56 



109 



107 



99 



IOI-8 



1870. 



95 



87 



94 



136 



125 



119 



1 09 



106 



1 19 1 



III 



113 



99 



109-4 



1871. 



92 



95 



122 



83 



114 



88 



86 



119 



'7 ; 



126 



96 



95 



100-2 



1872. 



103 



112 



106 



101 



95 



102 



III 



103 



97 ! 



lOI 



79 



81 



99-2 



1873. 



74 



73 



116 



98 



97 



98 



102 



93 



99 1 



110 



90 



100 



95-8 



1874. 



III 



103 



115 



103 



97 



104 



114 



97 



95 



88 



99 



89 



101-3 



1875. 1 



93 



87 



92 



ic6 



102 



lOI 



79 



98 



105 1 



89 



89 



79 



93-3 



5. It will be seen that, as far as correspondence with sun-spot periods 

 is concerned, Table II. gives results similar to those of Table I., exhibit- 

 ing the same kind of general correspondence, but exhibiting also a tem- 

 perature-oscillation of considerable magnitude, which may perhaps be 

 identified with a subsidiary solar-spot fluctuation as exhibited in the 

 curves of Messrs. De La Kue, Stewart, and Loewy (see Phil. Trans, for 

 1870), but which is out of proportion to it in relative magnitude. 



VOL. XXV. 2 T 



