1. It admits the roots of plants, and holds them in their position.
2. By a sponge-like action, it holds water for the uses of the plant.
3. It absorbs moisture from the atmosphere to supply the demands of plants.
How may it obtain heat?
What is the use of the air circulating among its particles?
Could most soils be brought to the highest state of fertility?
What is the first thing to be done?
Should its color be darkened?
4. It absorbs heat from the sun's rays to assist in the process of growth.
5. It admits air to circulate among roots, and supply them with a part of their food, while the oxygen of that air renders available the minerals of the soil; and its carbonic acid, being absorbed by the water in the soil, gives it the power of dissolving, and carrying into roots more inorganic matter than would be contained in purer water.