Plutarch Quaestiones Convivales 7.2.3

[3] This last Florus thought to be an idle foolery; but he said, that we should not forbear to search into the causes of the other things as if they were incomprehensible. I have found, said I, your design to draw me on to this discourse, that you yourself may afterward give us a solution of the other proposed difficulties.

In my opinion it is cold that causes this hardness in corn and pulse, by contracting and constipating their parts till the substance becomes close and extremely rigid; while heat is a dissolving and softening quality. Therefore those that cite this verse against Homer, do not justly reprehend him. For fields that are warm by nature, the air being likewise temperate, bear more mellow fruit than others. And therefore those seeds that fall immediately on the earth out of the sower’s hand, and are covered presently, and cherished by being covered, partake more of the moisture and heat that is in the earth. But those that strike against the oxen’s horns do not enjoy what Hesiod calls the best position, but seem to be scattered rather than sown; and therefore the cold either destroys them quite, or else, lighting upon them as they lie naked; condenseth their moisture, and makes them hard and woody. Thus stones that lie under ground and plant-animals have softer parts than those that lie above; and therefore stone-cutters bury the stones they would work, as if they designed to have them prepared and softened by the heat; but those that lie above ground are by the cold made hard, rigid, and very hurtful to the tools. And if corn lies long upon the floor, the grains become much harder than that which is presently carried away. And sometimes too a cold wind blowing whilst they winnow spoils the corn, as it hath happened at Philippi in Macedonia; and the chaff secures the grains whilst on the floor. For is it any wonder that husbandmen affirm, one ridge will bear soft and fruitful, and the very next to it hard and unfruitful corn? Or—which is stranger—that in the same bean-cod some beans are of this sort, some of the other, as more or less wind and moisture falls upon this or that?