Why is the middle of an apartment the safest place during a
thunder-storm?
Because, should a flash of lightning strike a building, or enter at any
of the windows, it will take its direction along the walls, without
injuring the centre of the room.
Combustion.
Why does amadou, or German tinder, readily inflame from flint and steel,
or from the sudden condensation of air?
Because it consists of a vegetable substance found on old trees, boiled
in water to extract its soluble parts, then dried and beat with a
mallet, to loosen its texture; and lastly, impregnated with a solution
of nitre.---Ure.
Why is a piece of paper lighted, by holding it in the air which rushes
out of a common lamp-glass?
Because of the high temperature of the current of air above the flame,
the condensation of which is by the chimney of the glass.
We do not quote these specimens in the precise order in which they occur
in the work, or to show the consecutive or connected interest of the
several articles. In many cases we select them for their brevity and
point of illustration.
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