A. The bottom part of the flame is overladen with hydrogen, raised from the tallow by the burning wick; and this half-burnt gas gives a purple tinge to the flame.
Q. Why is the inside of the flame of a candle hollow?
A. Because it is filled with vapour, raised from the candle by the heat of the wick.
Q. Describe the different parts of the flame of a common candle.
A. The flame consists of three cones. The innermost cone is hollow; the intermediate cone of a dingy purple hue; and the outside cone is yellow.
Q. Why is the intermediate cone of a flame purple, as well as the bottom of the flame.
A. Because the gases are not in a state of perfect combustion; but contain an excess of hydrogen, which gives this cone a purple tinge.
Q. Why is not the middle cone in a state of perfect combustion, as well as the outer cone?
A. Because the outer cone prevents the oxygen of the air from getting freely to the middle of the cone; and without the free access of oxygen gas, there is no such thing as complete combustion.