106 
COLONEL SABINE ON PERIODICAL LAWS DISCOVERABLE 
2nd. With this marked and very striking’ correspondence in the diurnal variation 
of this branch of the larg-er disturbances at Toronto and Hobarton, both as respects 
frequency of occurrence and comparative value, we notice minor distinctive features, 
which, considering the number of years embraced in the inquiry and the systematic 
mode of observation pursued, may claim to be regarded as indications of persistent 
rather than of accidental differences. Thus 9 p.m. is at Toronto the hour of maximum 
frequency and value ; both which maxima take place at Hobarton at 1 1 p.m., or two 
hours later. This feature is a well-marked one at both stations, and particularly in 
the aggregate values. In the period of the occurrences of the minimum of frequency 
and of value there is also a systematic difference, the period at Toronto being 2 and 
3 P.M., and at Hobarton 5 and 6 a.m. The features of minimum are however less 
distinctly marked than those of maximum. As both the numbers and the aggregate 
values diminish concurrently, it is obvious that the minimum is ascribable chiefly to 
the diminished frequency of the disturbances at those hours ; at Toronto 2 and 3 p.m. 
have decidedly the fewest easterly disturbances, and at Hobarton 5 and 6 a.m. as 
decidedly the fewest westerly. 
It may be useful occasionally to bring into notice, concurrently with the variations 
of the numbers and aggregate values, the variation of the average values of the 
disturbed observations. The average values at the several hours are the quotients 
obtained by dividing the aggregate values by the numbers, and the average value in 
the twenty-four hours constitutes the unit of the ratios which show the variation at 
the different hours. These ratios, for the easterly disturbances at Toronto and 
westerly at Hobarton, are contained in Table HI. 
Table HI. 
Hours of local 
Toronto. 
Hobarton. 
Hours of local 
Toronto. 
Hobarton. 
astronomical 
time. 
Easterly. 
Westerly. 
astronomical 
time. 
Easterly, 
Westerly. 
h 
h 
18 
0-85^ 
O-87'l 
6 
1-26^ 
MG'" 
19 
0-78 
0-77 
7 
1-15 
M8 
20 
21 
0-80 
0-77 
>0*81 
0-85 
0-80 
>0-81 
8 
9 
1-23 
1-39 
>1-23 
M4 
1-23 
>-l-22 
22 
0-78 
0-75 
10 
1-23 
1-20 
23 
0-85J 
0-82J 
11 
1-09 J 
1-43 J 
0 
0-78' 
0-77" 
12 
1-05"] 
1-281 
1 
0-81 
0-77 
13 
1*13 
1-23 
2 
3 
0-83 
0-89 
>0-87 
0-82 
0-77 
>0-79 
14 
15 
M7 
M2 
>1-11 
1-30 
M8 
>1-21 
4 
0-89 
0-82 
16 
1-23 
1-09 
5 
0-99 J 
0-80_, 
17 
0-95j 
1-20J 
It is here seen that the average value has a similar law of variation to that of the 
numbers and aggregate values : it is uniformly less during the hours of the day than 
in the hours of the night ; and has a maximum at Toronto at 9 p.m. and at Hobarton 
at 11 p.m. The epoch of minimum is not strongly marked at either station. 
