We sow a grain of wheat upside down, and the root grows reversing itself toward the earth and the stem toward the air, and this indicates intelligence; the stem at first grows joints in order to fonify itself against the stresses of the wind, and this indicates foreknowledge of a future event; toward the bottom these joints are closer to one another than toward the top, because according to the rules of mechanics, the stress of the wind that it must resist is greater at the bottom; the stem is hollow because in order to remain secure it must greatly decrease its weight without decreasing its strength at all or only a linle.