While in New Hampshire, Langmuir and Schaefer were surprised to learn that often the temperature of the clouds surrounding them was far below the freezing point, and yet ice did not form in the clouds. After the War, Schaefer experimented with a machine that created cold, moist air similar to the air found in clouds. To imitate the moist air of a cloud, Schaefer would breathe into the machine. Then he would drop into the freezer a bit of powder, sugar, or some other substance. For weeks and months he tried everything he could imagine. Nothing happened. No crystals of ice were formed. None of the substances would serve as the center of a snow crystal or raindrop.
One July morning, Schaefer was dropping in bits of various substances and watching the unsuccessful results. Finally, a friend suggested that they go to eat lunch, and Schaefer gladly went with him. As usual, he left the cover of the freezer up, since cold air sinks and would not escape from the box.
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