FROM ORDINARY DAYS OF THE ELEVEN YEARS 1890 TO 1900. 
251 
There is obviously a considerable “ accidental ” element in the results for individual 
months, especially in the shorter period waves. There is, however, an unmistakable 
seasonal variation in the phenomena in the 24-hour term in H. In the summer 
months, the difference, though small, is clearly positive, whereas in winter it is not 
merely negative bat very large, exceeding an hour of time. The fact is the seasonal 
variation in a x in H is much more pronounced in ordinary than in quiet days, the 
monthly values showing a range of 97° in the first case as compared with 71° in the 
second. 
Table XXXII.—Ordinary less Quiet Day Phase Angle in Minutes of Time. 
Month and 
season. 
24-hour term. 
12-hour term. 
8-hour term. 
6-hour term. 
H. 
V. 
H. 
V. 
H. 
Y. 
H. 
v- 1 
January. . . . 
- 68 
- 5 
+ 8 
-38 
- 4 
+ 5 
- 5 
- 8 
February . . . 
- 60 
+ 16 
- 1 
-23 
- 4 
+ 6 
+ 6 
+ 3 
March. 
_ 2 
+ 95 
+ 1 
- 3 
- 4 
+ 2 
_ 9 
- 4 
April. 
+ 19 
+ 76 
+ 7 
- 3 
+ 3 
+ 1 
+ 13 
+ 7 
May. 
+ 8 
+ 66 
- 14 
- 9 
+ 5 
- 1 
+ 4 
+ 14 
June. 
+ 3 
+ 48 
- 9 
- 3 
+ 8 
-13 
+ 24 
+ 7 
July . 
+ 12 
+ 58 
_ 2 
- 5 
+ 15 
- 1 
+ 18 
+ 10 
August .... 
+ 5 
+ 60 
+ i 
- 9 
- 1 
- 3 
- 3 
- 9 
September. . . 
- 31 
+ 100 
-25 
- 9 
-14 
_ 2 
+ 1 
- 14 
October .... 
- 25 
+ 112 
+ 1 
- 7 
0 
- i 
+ 4 
+ 8 
N ovember . . . 
- 69 
+ 55 
- 7 
-26 
- 4 
+ 14 
0 
- 3 
December . . . 
-100 
+ 67 
- 1 
-64 
- 5 
+ 6 
+ 14 
- 17 
Year. 
- 6-2 
+ 72-2 
- 3-0 
- 9-7 
-5-3 
+ 0-2 
+ 3-8 
+ o-i 
Winter .... 
- 82-6 
+ 29-8 
- 1-8 
-15-8 
- 4-5 
+ 8-1 
+ 2-2 
- 4-8 
Equinox. . . . 
- 9-0 
+ 94-9 
- 3-4 
- 5-5 
- 4-7 
o-o 
+ 3-1 
+ o-i 
Summer.... 
+ 7-5 
+ 58-7 
- 6-4 
- 6-7 
+ 5-3 
- 4-0 
+ 4-8 
+ 5 ■ 6 
The differences in both a x and a 2 in V also show a decided seasonal variation. They 
are algebraically greater in summer than in winter; but in the case of a x the 
equinoctial values are the largest of all. 
The variation of on in Y in the course" of the year is only 42^-° in ordinary as 
compared with 50j c in quiet days. The reduction in the annual range of a 2 in V on 
ordinary as compared with quiet days is fully larger. 
As regards a 3 and a 4 the differences between the ordinary and quiet day phase 
angles are small, and in the case of V practically evanescent for the mean diurnal 
inequality of the year. There is an irregularity in the incidence of the plus and minus 
signs in the case of the a 4 differences which shows the advisability of reserve even as 
regards the seasonal figures. In the case of a 3 the plus and minus signs show a regular 
incidence, so that more reliance can be placed on the seasonal values. It will be 
noticed that the seasonal variations in the two elements are exactly opposite. 
VOL. CCXVI.-A. 2 M 
