113 
According to the observations of Schwabe the numbers 
of groups of solar spots which occurred in the years 1858-68 
were as follows : — 
Year. 
1858 .. 
No. of 
Groups. 
.... 188 
Year. 
1864 .., 
No. of 
Groups, 
.... 130 
1859 .. 
.... 205 
1865 ... 
... 93 
1860 .. 
.... 211 
1866 ... 
45 
1861 .. 
.... 204 
1867 ... 
... 25 
1862 .. 
.... 160 
1868 ... 
... 101 
1863 .. 
.... 124 
The mean number is 135, and therefore it appears that 
during the five years 1858-62 the frequency of solar spots 
was above the average, and during the six years 1863-68 it 
was below. In order then to ascertain the effects of changes 
of solar activity upon the distribution of barometric pres- 
sure, temperature, and rainfall under different winds, the 
above table was divided into two tables, the first com- 
prising the l’esults for the five years 1858-62, when the 
number of solar spots was above the average, and the second 
those for the six years 1863-68, when the number of spots 
was below the average. The means of the numbers under 
each wind in both tables were then determined, and a com- 
parison of the two sets of results thus obtained showed, for 
each element, the nature of the changes which had taken 
place. 
Barometric Pressure. 
The mean pressures under different winds for the two 
periods, and their differences, are as follows : — 
N 
Mean Pressure 
1858-62. 
29-859 ... 
Mean Pressure 
1863-68. 
In. 
... 29-849 
Difference. 
In. 
. +0-010 
N.E 
29-890 ... 
... 29-801 
. +0-089 
E 
29-791 ... 
... 29-728 
. +0-063 
S.E 
29-672 ... 
.. 29-615 .... 
. +0 057 
S 
29-635 ... 
... 29-652 
. -0-017 
S.W 
29-604 ... 
... 29-719 
-0-115 
W 
29-684 ... 
... 29-789 
,. -0-105 
N.W 
29-810 ... 
... 29-805 .... 
.. +0-005 
