ON “QUIET” DAYS DUEINO THE ELEVEN YEARS 1S90 TO 1900, ETC. 
428 
§ 55. Consideiiiig tirst tlie Kew data in Table XLll. l)y themselves, we see that 
the phenomena presented in U and H by — i.e., the 24-hour term—are very similar 
to those already described in the case of the ranges. Absolutely considered, h is 
least in winter, and is, if anything, slightly greater at the equinoxes than at mid¬ 
summer ; the value of hja is conspicuously greatest in winter, and least in summer. 
The value of b/a for cu is also largest in vdnter, but in the case of H tlie summer 
value appears also in excess of the equinoctial. At Kew, the values of 6/a for c., 
are with one exception decidedly smaller than the corresponding value for ; in like 
manner the values for Cg are generally less than those for Co, and the values for less 
than those of Cg. In fact, in summer we have negative values for 6/a in for D, H 
and N. This may be accidental, as the numerical values appear very small, but we 
may at least conclude that sun-spot frequency e.xerts but a trilling inhuence on the 
value of Cj, at Kew. 
The reduction in the value of hja as we pass from c,, to Cg, and from Cg to cq, is also 
well shown at Wilhehnshaven, though not quite so prominently as at Kev'. Where 
the Wilhehnshaven data dider most notably from those at Kew, is in giving a larger 
value of 6/a for m than for cq, in both H and N. 
The values of 6/a found for Cj at Kew appear decidedly larger than those found in 
'fable XLl. for the range, or even as a nde than those found for the sum of the 
24 hourly differences. 
Comparing the diiferent elements at Kexv, we see that in Oj and tq the mean values 
of 6/a for the year are pretty much alike in H and N, and again in D and W, the 
values appearing slightly larger in H than in N, and very slightly smaller in W than 
in 1). The quantities tq and cq are tliemselves so small that conclusions based on the 
apparent differences in their case in the different elements, would possess an uncertain 
value. 
Comparing Wilhelmsliaven with Kew, we see that in the case of the Wilhelms- 
liaven values are in excess of the Kew for both a and 6 ; but the differences between 
the corresponding values for 6 are so small that the Kew xudues for 6/a are decidedly 
the larger. In the case of cq all the figures for Willielmshaven are in excess of tlie 
corresponding figures for Kew, except tlie value of 6/a in N. In m the Wilhehnshaven 
values of 6/o are the larger in W, but the smaller in H and N. In the 
Wilhelmsliaven values for 6 and 6/a are decidedly larger than the Kew, but still very 
small. W^hilst differences exist, there is a sufficiently close resemblance between the 
results at the two places to prove that the phenomena observed at Kew are by no 
means of an exceptional character. 
§ 56. The method of employing three groups of years has also lieen applied to the 
ranges and the sums of the 24 hourly differences in the mean diurnal inequalities for 
the year. The object was partly to obtain a comparison with Parc 8t. Maur through 
the intermediary of data published by iVIouEEAUX.* These data are the values of 
* ‘ Ana. dll Buieau Central Met^orologique de France,’ 1899, “ Memoires,” p. R.9. 
