IN THE MEAN EFFECTS OF THE LARGER MAGNETIC DISTURBANCES. 131 
Table V. 
Hours of 
Toronto time. 
Number of 
Westerly 
disturbances. 
Hours of 
Toronto time. 
Number of 
Westerly 
disturbances. 
Hours of 
Toronto time. 
Number of 
Westerly 
disturbances. 
6 A.M 
45 
2 P.M 
27 
10 P.M 
13 
7 A.M 
36 
3 P.M 
37 
11 P.M 
15 
8 A.M 
39 
4 P.M. 
32 
Midnight ... 
22 
9 A.M 
43 
5 P.M 
20 
1 A.M 
29 
10 A.M 
46 
6 P.M 
19 
2 A.M 
35 
11 A.M 
39 
7 P.M 
17 
1 3 A.M 
41 
Noon 
42 
8 P.M 
12 
4 A.M 
43 
1 P.M 
34 
9 P.M 
15 
5 A.M 
47 
In the next Table I have placed the excess in the number of westerly over the 
easterly disturbances, or of easterly over westerly disturbances, at every hour of the 
day and night. 
Table VI. 
Hours of 
Toronto time. 
E.xcess in the number of | 
disturbed observations, j 
Hours of 
Toronto time. 
Excess in the number of 
disturbed observations. 
6 A.M 
9 Westerly. i 
6 P.M 
8 Easterly. 
7 A.M 
0 
7 P.M 
28 Easterly. 
8 A.M 
20 Westerly. 
8 P.M 
53 Easterly. 
9 A.m 
20 Westerly. 
9 P.M 
71 Easterly. 
10 A.M 
21 Westerly. 
10 P.M 
70 Easterly. 
11 A.M 
9 Westerly. 
11 P.M 
42 Easterly. 
Noon 
23 tVesterly. j 
Midnight ... 
45 Easterly. 
1 P.M 
13 Westerly. 
1 A.M 
25 Easterly. 
2 PvM 
17 Westerly. 
2 A.M 
8 Easterly. 
3 P.M 
29 Westerly. 
3 A.M 
2 Westerly. 
4 P.M 
20 Westerly. 
4 A.M 
8 Westerly. 
5 P.M 
5 Westerly. 
5 A.M 
4 Westerly. 
We have in this Table a striking illustration of the periodical character of the 
larger disturbances, in the very different proportion of the numbers of easterly or 
westerly disturbances prevailing at the different hours. During the hours of the day, 
or notably from 8 a.m. to 4 p.m., westerly disturbances preponderate, whilst during 
the hours of the night, or notably from 7 p-m. to the early morning, easterly disturb- 
ances preponderate. The average excess in the number of westerly disturbances is 
19 in each of the nine hours, constituting the former period (8 a.m. to 4 p.m.), and of 
easterly disturbances 48 in each of the seven hours constituting the latter period 
(7 P.M. to 1 A.M.). The greatest excess of easterly disturbance occurs at 9 and 10 p.m., 
when about seven-tenths of the whole number of disturbed observations consists of 
deflections of the north end of the magnet towards the east. 
It is obvious from this systematically unequal distribution in the number of easterly 
and westerly disturbances of large amount at the different hours of the twenty-four, 
that unless it should be found on examination that the inequality in the proportion of 
the numbers should be counterbalanced by a similar inequality, but in the opposite 
s 2 
