406 DR. C. CHEER: ANALYSIS OF RESULTS FROM THE KEW MAGNETOGRAPHS 
in the two curves of fig. 20 should lie on the same radius vector, and the curves 
should be similar and similarly situated; also the curve in fig. 21 should be similar 
and similarly situated to the curves in fig. 20. This is obviously not the case. 
At 9 A.M. corresponding j^oints in the two curves in fig. 20 lie very nearly on the 
same radius vector, but thereafter the radius vector of the inner curve (sun-spot 
minimum) forges ahead, and continues ahead until the early morning. The points 
answering to 1 p.m. and 6 p.m. on the sun-spot minimum curve lie almost exactly 
on the same radii as the points answering to 2 p.m. and 7 p.m. on the sun-spot 
maximum curve. 
The difference between the shape of the curves in figs. 20 and 21 is conspicuous ; 
the latter cuive is much more nearly symmetrical with respect to the geographical 
meridian than the former. 
Sun-Spot Relations apparent in Fourier Coefficients. 
§ 48. To push the comparison further, I had Fourier coefficients calculated for the 
monthly inec[ualities of D and H from the two groups of years 1890, 1899, 1900 and 
1892 to 1895. Corresponding results for the last group of years were also calculated 
for Greenwich, making use of the values of the “a” and “6''' coefficients in the 
Greenwich annual publications. This gave results more strictly parallel to the Kew 
results than if one had employed the annual Greenwich values for the “c” coefficients. 
To facilitate intercomparison of the different cases, I have expressed the monthly 
values of the c’s as percentages of their mean. It is these percentage values that form 
the main part of Tables XXXV. and XXXVI. The absolute values for each month 
can however be obtained at once by combining the percentage with the absolute mean 
value given at the foot of the tables. The data for the 11 years have already 
appeared in Table XXIV., but it was desirable to show them in juxtaposition to the 
others. Besides the monthly data, the tables give the values of the c s for the three 
seasonal Inequalities, expressed in percentages of their mean, and likewise the absolute 
values of the c’s in the mean inequalities for the year.—(See pp. 408-411.) 
There are of course irregularities in the monthly values, but there is an unmistakable 
general tendency for the percentage values to rise in winter and fall in summer as we 
pass fi'om sun-spot minimum years through average years to sun-spot maximum years 
at Kew. 
In the case of D the Greenwich data stand on the far side, so to speak, of the Kew 
sun-spot maximum data. The same is true for tq in H, but in the case of the other 
three coelficients in H the Greenwich data approach most closely to the average year 
results for Kew. It would be of interest to know how much of the differences between 
Kew and Greenwich is due to difference in geographical position, and how much is due 
