That part which burns away during combustion is called organic matter; the ashes are called inorganic matter. The organic matter has become air, and hence we conclude that it was originally obtained from air. The inorganic matter has become earth, and was obtained from the soil.
This knowledge can do us no good except by the assistance of chemistry, which explains the properties of each part, and teaches us where it is to be found. It is not necessary for farmers to become chemists. All that is required is, that they should know enough of chemistry to understand the nature of the materials of which their crops are composed, and how those materials are to be used to the best advantage.
This amount of knowledge may be easily acquired, and should be possessed by every person, old or young, whether actually engaged in the cultivation of the soil or not. All are dependent on vegetable productions, not only for food, but for every comfort and convenience of life. It is the object of this book to teach children the first principles of agriculture: and it contains all that is absolutely necessary to an understanding of the practical operations of cultivation, etc.
Is organic matter lost after combustion?
Of what does it consist?
How large a part of plants is carbon?
We will first examine the organic part of plants, or that which is driven away during combustion or burning. This matter, though apparently lost, is only changed in form.
It consists of one solid substance, carbon (or charcoal), and three gases, oxygen, hydrogen and nitrogen. These four kinds of matter constitute nearly the whole of most plants, the ashes forming often less than one part in one hundred of their dry weight.
What do we mean by gas?
Does oxygen unite with other substances?