The Reason Why / A Careful Collection of Many Hundreds of Reasons for Things Which, Though Generally Believed, Are Imperfectly Understood

by Robert Kemp Philp

Fig. 2.—DIAGRAM SHOWING THE COMBUSTION OF A CANDLE.

246. Why does the lower part of the flame of a candle (D) burn of a blue colour?

Because the hydrogen of the tallow, having a stronger affinity for the oxygen of the air than carbon has, ignites first. Pure hydrogen burns with a bluish flame.

247. Why does the middle of the flame (C) look dark?

Because it is occupied with gaseous vapours, derived from the tallow, which have not yet ignited.

248. Why does the upper part of the flame (B) produce a bright yellow light?

Because it is in this part of the flame that the hydrogen of the candle, and the oxygen of the air, combine, and there is just sufficient carbon mixed with the hydrogen to improve its illuminating power.

249. Why is there a fringe of pale light (A) around the upper part of the flame?