The idea in fire-by-friction is=20 thus to increase the heat-generating friction to a point where the heat=20 created is sufficient to ignite the fuel (which in this case is=20 combustible material in the form of wood dust).
(The idea in fire-by-friction is=20; thus to increase; the heat-generating friction; to a point) (the heat=20; created; ) (the heat=20 created; is; sufficient to ignite the fuel; L:a point) (the heat=20 created; to ignite; the fuel (which in this case is=20 combustible material in the form of wood dust))
The idea in fire-by-friction is=20 the heat=20 the heat=20 created the heat=20 created
thus to increase created is to ignite
the heat-generating friction to a point
sufficient to ignite the fuel L:a point
the fuel (which in this case is=20 combustible material in the form of wood dust)