102 
The mean direction was S. 40° W., and mean daily move- 
ment 159 miles. The direction of the disturbing force was 
from S. 69° 3' W., and it had the effect of giving to the air 
a mean daily movement in that direction of 16 ‘86 miles. 
The mean magnetic declination for 1866 was 20° 28' W., 
and the mean for the eight years 1859-66 was 20° 5 2' *8 W. 
A line perpendicular to this is S. 69° 7 ,, 2 W. to N. 69° 7 / *2 E. 
Thus the mean direction in which the disturbing force acted 
during the eight years, differed only 4' *2 from that of a 
perpendicular to the magnetic meridian. The observations 
for 1866, therefore, fully bear out the conclusions to which 
I had been led from the discussion of those of the preceding 
seven years. 
It will be evident that a force which moves the atmos- 
phere daily, through an average distance of 16 to 17 miles, 
in a direction differing considerably from the mean direction 
of the wind, is an important element to be taken into 
account in framing a scientific system of forecasting the 
state of the weather. 
MICROSCOPICAL AND NATURAL HISTORY SECTION. 
January 4th, 1869. 
J. B. Dancer, F.R.A.S., President of the Section, in the 
Chair. 
Mr. Spencer H. Bickham, Jun., and Mr. James Higgin 
were elected members of the Section. 
Mr. A. G. Latham exhibited a beautiful set of microscopic 
slides, and read a short paper in illustration of the various 
