125 
The mean ratio is 3 01, and the ratios for the years of 
maximum solar spot frequency are all above this mean, 
while those for minimum years are all below it, with only 
one unimportant exception. 
In order now to eliminate as far as possible the effects of 
accidental disturbing causes we may take the means of the 
ratios of every three successive years, and in this way we 
obtain the corrected ratios in the fifth column of the above 
table. For convenience of comparison I have added in the 
sixth column the number of groups of solar spots observed 
in each year by Schwabe, and a glance at the two sets of 
numbers will show the remarkably close agreement which 
exists between them in the times of their maxima and 
minima, which seems to me fully to justify the conclusion 
that both classes of phenomena are intimately connected, 
either as cause and effect, or as effects of the same cause. 
Excluding the amounts of rain which fell during calms 
the corrected ratios become : — 
1855 ... 
... 2-77 
1860 .... 
.. 6-42 
1856 ... 
... 2-15 
1861 .... 
.. 4-37 
1857 ... 
... 3-32 
1862 .... 
.. 4-04 
1858 ... 
... 5-40 
1863 .... 
.. 2-80 
1859 ... 
... 6-31 
It will be observed that the course of these numbers is 
almost identical with that of the numbers obtained when 
the amounts of rain which fell during calms are combined 
with those which fell under north-east, east, and north-west 
winds. 
The close agreement which has thus been shown to exist 
at St. Petersburg between the times of maximum and 
minimum frequency of solar spots, and those of the varia- 
tions in the distribution of rainfall under different winds, 
gives increased value to the results derived from the Oxford 
observations, and affords additional support to the hypo- 
thesis I ventured to advance in a former paper — that 
