The pupils examined stones, pebbles, and shells. They found some rough, some smooth. Through the teacher's questions—"Why are some rough?" "Why are some smooth?" "If those having a smooth surface now were once rough, what has become of the particles which must have broken away?"—the class was led to express opinions until the final generalization was made: Soil may be formed from the breaking up of rocks and shells.
Each topic was treated in a similar manner, the specific qualities of the specimen being brought out, until we were able to make the summary:—
"Soil is made from decayed rocks and shells; soil is made from decayed leaves; the rocks make a coarse soil called sand; the wood and leaves make finer soil called loam; the mixture of these soils makes productive soil."
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This summary led to the next lesson, "The Productive Qualities of Soil." The question was asked, "How can we determine the productive quality of soil?"
"We can plant some seeds in each kind of soil," said a child. Several pupils volunteered to bring pots of earth.
Ready for the experiment, we proceeded to analyze as follows the soil brought by the children:—