CHAPTEK XIY. 
OBSERVATIONS ON HIGH CURRENTS. 
As suggested by our bonfire, the air circulates. If 
this is true, there must be currents in the air far above 
the earth that correspond to surface winds, but fiow 
in opposite directions. Can we learn anything about 
those ? Indeed we can. The clouds and the volcanoes 
shall teach us. 
Every one has the privilege of observing the clouds, 
and has noticed that often there are two sets, possibly 
three layers, one above the other, moving in different 
directions. The higher clouds, of course, are carried 
along by the upper air currents, which for the want 
of a better name we will call the upper air currents. 
If we will observe the high clouds and record our 
observations for some time, we can learn much about 
the upper currents. 
Again, the ascending smoke of volcanic eruptions 
has furnished interesting facts. In 1812 a volcano on 
the Isle of St. Yincent forced its ashes up into the 
higher air. Below, the wind carried them off toward 
the west; in the upper regions they were borne toward 
the northeast, and settled down on vessels more than 
a hundred miles to the northeast of the volcano. 
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