17. Is breathing a kind of combustion?
It is. In the breathing of animals, the burning of coals, or of wood, or candles, &c., similar changes occur. The oxygen of the air combines with the carbon of the substance said to be burnt, and forms carbonic acid gas, which unfits the air for the purposes of either breathing or of burning, until it has been renewed by admixture with the air.
It is one of the elementary bodies, and is very abundant throughout nature. It abounds mostly in vegetable substances, but is also contained in animal bodies, and in minerals. The form in which it is most familiar to us is that of charcoal, which is carbon almost pure.
19. What is meant by an elementary body?
An elementary body is one of those substances in which chemistry is unable to discover more than one constituent. For instance, the chemist finds that water is composed of oxygen and hydrogen. Water is therefore a compound body. But carbon consists of carbon only, and therefore it is called a simple, or elementary body.
"Where no wood is, there the fire goeth out: so where there is no tale-bearer, the strife ceaseth."—Proverbs xxvi.