578 



Prof. B. Stewart on the Daily 



Table I. — Containing Monthly Means o£ Daily Temperatnre-Eange 

 expressed in Eahrenheifc degrees. 



X ear. 



J an. 





iVLar. 



Apr. 



May. 



J line. 



uiy. 



Aug. 

 



ioopt. 





AT 



JN OV. 

 







Mean 

 of year. 



1855. 































































7-0 



91 



11-8 



17-2 



16-0 



i6-6 



i5'9 



i6-5 



i6-6 



10-9 



8-0 



8-8 



12-87 



1856. 



7-4 



77 



IO"2 



15-0 



I3-I 



16-9 



17-2 



17-5 



15-2 



I2-0 



lO'I 



lo-o 



12-69 



1857. 



77 



I2'9 



11-9 



i3"5 



17-9 



21-2 



19-2 



17-9 



14-8 



12-3 



8-9 



8-9 





1858. 



11-3 



9-2 



i4'3 



15-9 



16-6 



19-8 



i7'5 



19-3 



15-1 



i3'5 



112 



9 '4 



14-42 



1859. 



'9-5 



I2'I 



121 



15-8 



16-6 



17-1 



2I-0 



i8-8 



15-4 



12-8 



12-5 



10-5 



14-52 



i860. 



io*3 



II-6 



11-5 





17-4 



13-0 



15-8 



13-0 



15-0 



11-9 



9-6 



9-3 



i2-8o 



1861. 



IO"2 



io'8 



12"I 



16-4 



i6'6 



I5-I 



15-1 



i8-2 



16-3 



12-9 



13*4 



lo-i 



i3"93 



1862. 



9-2 



7-2 



10-3 



12-7 



15-1 



i5"i 



15-9 



15-9 



14-8 



12-4 



1 1-2 



9-6 



i2"45 



1863. 



9-8 



I2"2 



i5"4 



17-1 



17-1 



i6-6 



21-4 



16-9 



15-9 



11-5 



11-4 



10-5 



14-65 



1864. 



9'3 



9-8 



14-1 



16-7 



17*3 



17-1 



20-7 



20'7 



15-4 



ii'5 



i3"3 



9-2 



i4"59 



1865. 



9*4 



9'5 



io'8 



21-5 



18-6 



i9"5 



18-5 



17-0 



20'5 



14-8 



12-4 



7-5 



15-00 



1866. 



97 



10-5 



II-5 



14-3 



17-9 



i8-5 



17-5 



i6-2 



12-3 



11-9 



12-3 



10-7 



13-61 



1867. 



II-2 



9-6 



IO-6 



14*2 



17-3 



18-4 



177 



17-9 



16-0 



147 



I2-I 



lo-i 



14-15 



I 000. 



^ 5 



12*3 



13 ^ 





19-9 



21-9 



22-4 



10 a 



19-1 



157 



10-4 



9 



1 5 '45 



1869. 



io*o 



lOI 



IO-5 



i7'6 



14-8 



17-9 



2I-I 



18-9 



15-2 



H'3 



ir8 



9-1 



14-27 



1870. 



87 



8-7 



117 



22-1 



21-4 



21-1 



20-2 



.8-7 



18-9 



14-6 



12-4 



9-1 



15-63 



1871. 



8-4 



o*< 



y J 



I <;"2 



J J 



y J 



15-6 



15-9 



20'9 



I -Q 



i6-6 



10-6 



8-7 



14-02 



1872. 



9*4 



II-2 



13-2 



16-3 



i6-3 



18-1 



20-6 



i8-i 



i5"4 



i3'3 



87 



TA: 



14-C0 



1873. 



6-8 



7-3 



14-4 



15-9 



i6-6 



17-3 



i8-8 



16-4 



15-8 



14*5 



9-9 



9-2 



13-57 



1874. 



IO-2 



10-3 



14-5 



i6-8 



i6-7 



18-4 



2I-I 



17-0 



15-1 



11-6 



10-9 



8-2 



14-23 



1875. 



8-5 



8-7 



11-5 



17-2 



17-6 



17-9 



14-7 



17-3 



16-7 



II-8 



9-8 



7'3 



13-25 



Mean of 1 

 21 years. J 



9-17 



lO'OI 



12-45 



l6-22 



17-16 



1 



17-77 18-49 



17-61 



15-88 



13-12 



I i-oo 



9-17 



14-00 



B. Variations of Long Period. 



3. It wdll be seen from Table I, that the various yearly means exhibit 

 considerable differences amongst themselves. 



Thus the first two 3^ears (1855 and 1856), as well as the last year (1875), 

 exhibit comparatively small values, and suggest the interesting question 

 whether the yearly mean daily range does not depend, among other 

 things, on the state o£ the sun's surface with regard to spots. There are 

 three minimum sun-spofc years in Table L, say 1856, 1866, and 1875, 

 and two maximum years, say 1859 and 1870 ; and accordingly w^e find 

 that the three former correspond to small ranges, namely 12"'69, 13°'61, 

 13°-25, and the two latter to large ranges, namely 14°-52, 15°-63. But 

 on the other hand, and against this evidence. Table I. records a tempera- 

 ture-oscillation between 1859 and 1866 as great, or nearly as great, as 

 any which apparently corresponds to sun-spot variation. 



4. Before discussing this point further, it will be desirable to recon- 

 struct the elements of Table 1. on a somewhat different principle. 



To perceive this let us assume that the influence of the sun upon the 

 daily range of temperature is really greater during years of maximum 

 than during years of minimum sun-spot frequency. Now if this influ- 

 ence is identical with or follows laws similar to the heating-influence of 



