ON “QUIET” DAYS DURING THE ELEVEN YEARS 1890 TO 1900, ETC. 
418 
refer to G.M.T., but the differences between the values at the same season of the year 
would, of course, be the same if local solar time were used. 
In the case of the mean inequalities for the year, with the exception of the G-hour 
term in H and N, we see a decided decrease of the angle in passing from years of 
sun-spot minimum, through average years, to years of sun-spot maximum. This 
means, as already explained, a later hour of occurrence of the maximum in the Fourier 
series’ term. In the case of the excess of the angle for the sun-spot minimum over 
the sun-spot maximum years varies from 2° 47'—answering to about 11 minutes in time 
•—in N, to 4° 4G'—or about 19 minutes in time—in H; the average difference in 
time for the four elements, I), W, H, and N, is about 1 5h minutes. The correspond¬ 
ing average differences in time in a., and are about 18 minutes and 14 minutes 
respectively. In the algebraic mean of the differences for the four elements almost 
exactly vanishes. 
In D in a^, a.,, and a,, the difference in angle between sun-spot minimum and sun¬ 
spot maximum is conspicuously greatest in winter, and is least in summer. In H the 
difference in in winter is opposite in sign to what it is at the other seasons. With 
the exceptions of in D, and in H, the differences between the angles for sun-spot 
minimum and sun-spot maximum are much the same for the equinox as for the 
whole year. 
