In view of the significance of nature, we arrive at a new fact, the nature is a discipline. This use of the world includes the preceding uses, as parts of itself. Space, time, society, labor, climate, food, locomotion, the animals, the mechanical forces, give us sincerest lessons, day by day, whose meaning is unlimited. They educate both the Understanding and the Reason. Every property of matter is a school for the understanding, - its solidity or resistance, its inertia, its extension, its figure, its divisibility.