160 ON MAGNETIC DISTURBANCES AT TORONTO. 
1862. For the purpose of comparison, the corresponding ratios for 
the series Ist July, 1843, to 30th June, 1848, and derived from the 
3rd Toronto volume, have been introduced. The ratios in table IT. 
are identical with those in the printed volume, but in table I. the ag- 
gregate sums at the separate six observation hours, are expressed i in 
terms of the average of the same siz aggregate sums, whereas in the 
printed volume, the unit employed is the average of the twenty-four. 
aggregate sums, 
In table III. the yearly aggregates relate in every case to the year, 
ending 30th June. It has been thus arranged, partly, that the later series 
might harmonise better with that of 1844-48, and also for the sake of 
including the year ending 30th June, 1854, and a few of the later 
months in 1855. The year ending 30th June, 1856, includes for. the 
declination an approximation to the aggregate value of disturbances in 
July, 1855, calculated on the supposition that it bore to the aggregates, 
in the concluding months of 1855, the same ratio as that founded by. 
the whole series, 1856 to 1862. Approximate values of the disturban- 
ces of the vertical force for July, and of the horizontal force, total 
force, and inclination, both for July and August, 1855, have been. 
similarly found and employed in calculating the aggregates for the 
year ending 30th June 1856. 
In table IV., the sums in table IIT. have been expressed in terms 
of the average of the seven yearly sums, terminating 30th June, 1862. 
These units of reference are employed to show better the periodic 
character of the last seven years; and though not adapted to exhibit 
so distinctly the position of the several years, 1844-48, in the decen- 
nial period in which the years are included, they render sufficiently 
apparent the relative magnitude of the aggregates in the two series. 
Columns 2 and 3 give the results of the observations of M. Schwabe on 
the solar spots. 
On comparing the series 1856-62, in table I., with that of 1844—4§ 
the general correspondence in the ratio is very apparent, the chief 
characteristic difference in the later series being, that the distinctive 
features of different parts of the day, as shown in the earlier series, are 
somewhat softened down; the ratios that are above unity being on the 
most part less, and those that are less than unity, being greater in the 
ater than the earlier series. In one case only, namely, of the distur- 
bances that increase the horizontal force at 8a.m., do the ratios lie 
on opposite sides of unity in the two series; but on referring to table, 
