IN THE MEAN EFFECTS OF THE LARGER MAGNETIC DISTURBANCES. 105 
Table I. 
Hours of local 
astro uomical 
time. 
Toronto. 
Hobarton. 
Hours of local 
astronomical 
time. 
Numbers. 
Values. 
Numbers. 
Values. 
h 
h 
18 
0-86 
0-69 
0*54 
0-44 
18 
19 
0-83 
0-61 
0-73 
0-53 
19 
20 
0-82 
0*62 
0-86 
0-70 
20 
21 
0-81 
0-59 
0-73 
0-55 
21 
22 
0*82 
0-60 
0-77 
0-55 
22 
23 
0-81 
0-65 
0-80 
0-62 
23 
0 
0-61 
0-45 
0-87 
0’65 
0 
1 
0-57 
0*44 
0-87 
0-64 
1 
2 
0*44 
0-34 
0-92 
0*71 
2 
3 . 
0-38 
0-33 
0-76 
0-56 
3 
4 
0-52 
0-43 
0-73 
0*56 
4 
5 
0*54 
0-50 
0-67 
0-52 
5 
6 
0-78 
0-94 
066 
0-72 
6 
7 
MO 
M7 
0-94 
1-04 
7 ' 
8 
1-31 
1-58 
1-23 
1-31 
8 
9 
1-88 
2-47 
1-54 
1-79 
9 
10 
1-67 
1-95 
1-72 
1-96 
10 
11 
1-61 
1-66 
1-72 
2*31 
11 
12 
1-59 
1-57 
1-71 
2-05 
12 
13 
1-49 
1-60 
1-48 
1-72 
13 
14 
M7 
1-30 
1-23 
1-52 
14 
15 
1-18 
1-25 
Ml 
1-26 
15 
16 
MO 
1-29 
0-82 
0*84 
16 
17 
1-09 
0-98 
0*34 
0-47 
17 
On examining this Table, we perceive, — 
1st. That in this division of the disturbed observations, namely, those which are 
easterly at Toronto and westerly at Hobarton, there is a well-marked and systematic 
variation dependent on hour in the numbers of the disturbed observations and in 
their aggregate values. The most obvious feature is, that at both stations there are 
fewer disturbances, and their aggregate values are less in the hours of the day than in 
those of the night ; and as the stations differ from each other nine hours in longitude, 
the dependence of the variation is on the hours of local and not on those of absolute 
time. If we divide the twenty-four hours at each station into four equal divisions 
according to the hours of local time, viz. 6 to 11 a.m., noon to 5 p.m., 6 p.m. to 11 p.m., 
and midnight to 5 a.m., the 1st and 2nd divisions being those of the day, and the 3rd 
and 4th those of the night, we find the mean ratios to be as follows, — the mean 
hourly number, and the mean hourly aggregate value in the whole period being still 
considered as the respective units. 
Table II. 
Hours of local time. 
Toronto. 
Hobarton. 
Numbers. 
Values. 
Numbers. 
Values. 
Day ... . 
6 to 11 A.M. inclusive 
Noon to 5 P.M. inclusive ... 
0-82 
0-51 
0-63 
0-41 
0*74 
0-80 
0-57 
0-61 
Night < 
6 P.M. to 11 P.M. inclusive... 
1-40 
1-63 
1-30 
1*52 
Midnight to 5 a.m. inclusive 
1-27 
1-33 
M5 
1»31 
MDCCCLIf. 
