80 
DR. C. CHREE: SOME PHENOMENA OF SUNSPOTS AND OF 
of Wolf’s formula (l) to diurnal inequality ranges showed that when Kew “ quiet” 
days were considered—the information for other than “ quiet ” days at Kew is still 
lacking—inclination (I) was the element for which the constant m was largest, i.e., for 
which the greatest percentage increase of range occurred for a given increase in 
sunspot frequency. Next to I came H. 
Values of I are not recorded directly by the magnetographs, but have to be 
calculated from the recorded values of H and V (vertical force). Thus it would he a 
very difficult, if not practically impossible, task to find absolute daily ranges of I. 
Daily ranges of H, on the other hand, are as easily obtained as those of D, provided 
one neglects the corrections required to allow for the variation of temperature. At 
Kew such neglect seldom causes an error as large as 2y (ly = 1 x 10“® C.G.S.) in the 
absolute daily range, and often is without any effect, and for investigations such as 
the present the slight increase in the accuracy of individual daily ranges that might 
ensue from the application of temperature corrections would be immaterial. 
In 1908 a grant was obtained from the Government Grant Committee for the 
measurement of all Kew H and V curves of the 11 years 1890 to 1900, and the work 
naturally included the determijiation of the absolute daily ranges, which thus became 
available for the present enquiry. 
The increase of sensitiveness in the method expected from the substitution of H for 
D ranges was consideralfie, as will be seen l)y reference to Talde I. Adopting the 
notation of (l), 100m represents the percentage increase in the range of the diurnal 
inequality answering to an increase in Wolfer’s sunspot frequency from 0 to 100. 
The results to which the letter A is attached in Table I. were obtained by least squares, 
those to which the letter B is attached by what I have called the “ method of 
groups.” 
Table I.—Values of 100m at Kew. 
Method. 
D. 
H. 
H value -f- D value. 
From range of mean diurnal j 
A 
0-71 
1-07 
1-51 
inequality for the year . . | 
B 
0-66 
1-04 
1-58 
From inequality ranges of 12 f 
A 
0-G3 
0-89 
1-41 
months of the year individu-< 
ally considered.[_ 
B 
0-68 
1-00 
1-47 
If, then, the relation between absolute ranges on individual days and sunspots follows 
snmlai laws to those presented m the case of the range of the diurnal inequality, we 
should expect the difierences disclosed by investigations such as those described 
§§ ^ and 6 to lie increased some 50 per cent, when D ranges are replaced by II 
ranges. 
