"And the strong shall be as tow, and the maker of it as a spark, and they shall both burn together, and none shall quench them."—Isaiah i.
105. Why is there so little smoke when the fire is red?
Because the hydrogen and the volatile parts of the coal have already been driven off and consumed, and the combustion that continues is principally caused by the carbon of the coals, and the oxygen of the air.
106. Will carbon, burnt in oxygen, produce flame and smoke?
It burns brightly, but it produces neither flame nor smoke.
107. Why do not charcoal and coke fires give flame?
Because the hydrogen has been driven off by the processes by which charcoal and coke are made.