CHAPTEK XIII. 
WINDS. 
After making observations for some time and 
comparing different items in my record, I discovered 
that the barometer rose or fell at times when, as far 
as I could see, there was no reason for it. I con¬ 
cluded from this that there must be other causes 
about which I, at present, knew nothing. I there¬ 
fore began to study the wind. 
In the first place, what is the wind ? It is some¬ 
thing I can not see, though I can feel its effects. I 
can see how it bends down the trees and carries along 
light objects like feathers and down. It must be the 
air in motion. Xow the question comes, What makes 
it move ? 
I made a little paper windmill and attached a 
crank to it to which I fastened a paper man holding a 
saw across a log. When I held this mill over the hot 
stove it whirled around and made the man go through 
the motions of sawing wood. There was evidently 
an upward wind from the stove which set my ma¬ 
chinery in motion. When there was little fire, the 
mill moved slowly. When I held it over the register, 
the hot air from the furnace also turned it around. 
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