Q. What is the cause of the combustion of fire?
A. The carbon of fuel unites with the oxygen of the air, and forms carbonic acid gas.
Q. What is the cause of the combustion of a candle or lamp?
A. The carbon of the oil or tallow unites with the oxygen of the air, and forms carbonic acid gas.
Q. What is the cause of spontaneous combustion?
A. The piled-up goods ferment from heat and damp; and (during fermentation) carbonic acid gas is formed, as in the two former cases.
Q. Does the heat of the human body arise from the same cause as the heat of fire?
A. Yes, precisely. The carbon of the blood, combining with the oxygen of air inhaled, produces carbonic acid gas, which is attended with combustion.
Q. If animal heat is produced by combustion, why does not the human body burn up like a coal or candle?