197 
differing from those found by direct observation by Prof. 
Spörer who, for the heliocentric latitude 1° 55’ North finds 
a period of 24.54 days. The value 24.108 days, if considered 
10 represent the period of rotation for equatorial zones, is there- 
fore not more in discordance with the results of direct observa- 
lion than might be expected from the totally different modes 
of calculation. 
А second question bears relation to a possible influence of 
the frequency of sunspots in the period of rotation, an influence 
which seems to be observable, and that in no inconsiderable 
degree, in the values for this period deduced from sunspot 
observations by Mr. Bérorousky (1) who finds a greater angular 
Velocity when the quantity of spots is a minimum than when 
it attains а maximum value. 
The mean monthly relative number of sunspots taken from 
Prof. Worrs' tables. corresponding with the ten groups, are: 
Ne 2. 12.1 
2 65.9 
5 119.9 
4 75.4 
5 21.2 
6 16.5 
7 15.7 
5 55.2 
9 61.2 
10 46.6 
The mean valne for the groups 1, 5, 6, 7, 10 is: 22.42, 
that for the groups 2, 5, 4, 8, 9: 75.12. 
The following table shows the sums for different values of p 
relating to these two series for barometric means and baro- 
melric ranges: 
таз ЕЕЕ ЕД 
) Bulletin astronomique. Tome IV. Févr. 1887. 
