FIG. 64
A SPIRIT LEVEL
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Experiment 46. To make a spirit level.
The spirit level (Fig. 64) is simply a curved
glass tube filled with alcohol except for the bubble and closed at
both ends. The curve of the tube is part of a circle.
Make a spirit level as follows: Take a piece
of No. 4 tube about 7 inches long, heat a space about 3 inches long
in the lamp flame, turn constantly, and when soft remove from the
flame, hold both ends and allow the center to sink into a slight
curve (1. Fig. 65).
FIG. 65
MAKING A SPIRIT LEVEL
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Let the tube cool, mark the center of the
curve with ink, and make marks 2 inches from the center on each side.
Hold the tube crosswise in the lamp flame, heat
at one mark, draw down the tube and close it (2).
In a similar manner draw down the tube at the
other mark but do not close it (3).
Let the tube cool and fill it with alcohol to
the level shown in 4. To do this easily make the pipette (5), such
alcohol into it within about 1 inch of the top, put your finger over
the top, insert the lower end of the pipette to the bottom of 4, and
remove your finger.
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