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Nobody has ever thought of a way to regulate the warmth or
coldness, dryness or humidity of air outdoors. The most we can
do is to find out what the weather is going to be like, and then
prepare for it. ___1___
it is quite a different matter. By means of air-conditioning, we
can clean the air, give it just the right amount of moisture and
keep it as warm or cool as we like. Air-conditioning is used
not only in houses, offices and public buildings, but also in
buses, railway cars, airplanes and ships; in mines thousands of
feet beneath the surface of the earth; and in places where
___2___ products are stored.
It has a wide variety of uses in industry where it helps to ___3___
the quality of products that are being manufactured. Properly
conditioned air is a great aid to the health, comfort and ___4___
of people who work or live indoors or in ___5___.
To understand just what air conditioning is about, we must
first know what air is and what it does. Air is made up chiefly
of a ___6___
of two gases -- oxygen and nitrogen. It has very small
quantities of some other gases, and some water vapor. Air also
contains ___7___, such as
dust, soot and smoke. Too much of these in the air we breathe
interferes with the life-giving oxygen that we need, and ___8___.
Air varies widely in the amount of humidity it contains.
Sometimes, air is practically dry; sometimes it is so ___9___
with moisture that it will hold no more.
One of the most important things that an air-conditioning
system does is to keep the air from getting ___10___.
It has devices that chill the air and carry away the water that
is forced out of it. |
