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[Herriott C. <tra...@bi...>]

Story of Mankind.' Black Tinder.--Tinder that is black by previous
charring, or from any other cause, ignites in the sun far sooner than
light-coloured tinder. Fire by conversion of motion into heat.--General
Remarks.--When a moving body is arrested, heat is given out; the
quantity of heat being in exact proportion to the mass, multiplied into
the square of its velocity. Thus if a cannon ball be fired at an iron
target, both it and the ball become exceedingly hot. There is even a
flash of light when the velocity of the ball is very high. When bullets
are fire