What is water composed of?
If analyzed, what does it yield?
How do plants obtain their hydrogen and oxygen?
Let us now consider the three gases, hydrogen, oxygen and nitrogen, which constitute the remainder of the organic part of plants.
Hydrogen and oxygen compose water, which, if analyzed, yields simply these two gases. Plants perform such analysis, and in this way are able to obtain a sufficient supply of these materials, as their sap is composed chiefly of water. Whenever vegetable matter is destroyed by burning, decay, or otherwise, its hydrogen and oxygen unite and form water, which is parted with usually in the form of an invisible vapor. The atmosphere of course contains greater or less quantities of watery vapor arising from this cause and from the evaporation of liquid water. This vapor condenses, forming rains, etc.
Hydrogen and oxygen are never taken into consideration in manuring lands, as they are so readily obtained from the water constituting the sap of the plant, and consequently should not occupy our attention in this book.
NITROGEN.
If vegetable matter be destroyed, what becomes of these constituents?
What is the remaining organic constituent?
Why is it worthy of close attention?