IN THE ME^N EFFECTS OF THE LARGER MAGNETIC DISTURBANCES. 113 
same as were deduced in my former paper from the observations in 1843, 1844 and 
1845. From the confirmation which has now been derived from the observations in 
the following years, 1846, 1847 and 1848, they may perhaps claim to be regarded as 
the exponents of persistent natural laws. 
III. Variation in the numbers and aggregate values of the disturbed observations 
in different years. 
Table XIII. exhibits the ratios of the numbers and aggregate values of the disturbed 
observations at Toronto and Hobarton in the different years, to the average annual 
number and aggregate value respectively*. 
Table XIII. 
Years. 
Numbers. 
Values. 
Years. 
Toronto. 
Hobarton. 
Toronto. 
Hobarton. 
1843 
0-68 
0-52 
0-55 
0-48 
1843. 
1844 
0-76 
0-81 
0-73 
0*82 
1844. 
1845 
0-72 
0-72 
0-62 
0-67 
1845. 
1846 
1-31 
1-09 
1-26 
1-03 
1846. 
1847 
1-19 
1-36 
1*40 
1-44 
1847. 
1848 
1-37 
1-50 
1-43 
1-60 
1848. 
On the first aspect of this Table, two features of principal interest present them- 
selves ; first, there is a considerable variation in the numbers and values of the 
disturbed observations in different years ; and second, there is a remarkable corre- 
spondence in the variation in different years at the two stations. 
Before we proceed to consider the first of these features, which is obviously one of 
great importance, it may be desirable, in reference to the correspondence at the two 
stations, to state more precisely than has been done previously, the degree of simulta- 
neity at the two stations of the observations from which the conclusions are derived. 
The weeks of observation commenced at both stations at midnight on the Sun- 
days, and terminated an hour before midnight on the Saturdays. As these epochs 
were of local time, the week of observation commenced at Hobarton at S'*, and at 
Toronto at IS*’ of Gottingen time of the same astronomical day; and terminated at 
Hobarton at 2**, and at Toronto at 17** of Gottingen time. There were consequently 
fifteen hours at the commencement of each week (S*’ to 17'’ Gottingen) in which 
observations were made at Hobarton without simultaneous observations at Toronto ; 
and fifteen hours at the termination of each week in which observations were made 
at Toronto without simultaneous observations at Hobarton. There were also nine 
hours in every week, between the conclusion of the one week at Toronto and the 
* As 1843 and 1848 are only half years, the ratios are taken to the half average annual number and half 
average aggregate value in the five years. 
MDCCCLII. Q 
