120 
HAROLD’S DISCUSSIONS. 
cold winds suddenly dropping down upon us from 
the northern points of the compass. 
BELTS OF HIGH PRESSURE. 
Another interesting thing must be mentioned. 
The average annual barometer is 29.8 at the equator, 
in the horse latitudes it is 30.2, and in the high lati¬ 
tudes, 30 inches. Thus we see that there is a belt of 
high pressure in the horse latitudes the year round, 
and particularly 
over the Atlantic 
Ocean. There 
seems to be a 
hill of atmos¬ 
phere over the 
Sargasso Sea, 
from which the 
air flows out in 
all directions. 
What can the 
cause of this be ? 
It seems to me 
it is this : the air 
S moving north 
Fig. 61.—Wind belts or zones, and polar crowded to- 
caps. 
gether the lar- 
ther it moves poleward. The meridians are nearly 
seventy miles apart at the equator, but at the poles 
they meet. At latitude 30° the distance between 
the meridians is only 60 miles; at latitude 40° it is 
about 53 miles. Thus it will be seen that air spread 
