418 DR. C. CHREE: ANALYSIS OF RESULTS YROM THE KEW MAGNETOGRAPHS 
§ 5'J. liauu-es based on only bve quiet days are somewhat uncertain, and calcula¬ 
tions by least squares are somewhat laborious, I thus investigated a second method 
of finding values of a and h, which seems to work satisfactorily. It makes use 
of values deduced from the three groups of years 1892 to 1895, 1890, 1899, 1900, and 
1890 to 1900. The method will be most easily grasped by considering a concrete 
case. For this purpose, let us consider the declination range for January. We have 
the following data 
Inequality from 1892 to 1895 . . Range 4'-97 Sun-spot frequency . . 72-65 
„ „ 1890,1899,1900. „ 3'-26 „ „ . • U'lO 
Differences . . . . 1‘71 61-25 
Consequent value for b = l'7l -P 61-25 = 279 X 10 
Inequality from 1890 to 1900 . . Range 4'-07 Sun-spot frequency . . 39-8. 
Hence value for a = 4'-07 — 39-8 X 279 X 10“^ = 2'-96. 
And value for h/a = ’0279 -P 2-96 = 94 X 10 f 
I'he values obtained in this waiy for the ranges and for the sums of the 24 hourly 
differences in the diurnal inequahties of D and H are given in Tables XLI. 
