The air works for him. The atmosphere, a sharp solvent, drinks the essence and spirit of every solid on the globe,--a menstruum which melts the mountains into it. Air is matter subdued by heat. As the sea is the grand receptacle of all rivers, so the air is the receptacle from which all things spring, and into which they all return. The invisible and creeping air takes form and solid mass. Our senses are sceptics, and believe only the impression of the moment, and do not believe the chemical fact that these huge mountain-chains are made up of gases and rolling wind. But Nature is as subtle as she is strong. She turns her capital day by day; deals never with dead, but ever with quick subjects. All things are flowing, even those that seem immovable. The adamant is always passing into smoke. The plants imbibe the materials which they want from the air and the ground. They burn, that is, exhale and decompose their own bodies into the air and earth again. The animal burns, or undergoes the like perpetual consumption. The earth burns,--the mountains burn and decompose,--slower, but incessantly. It is almost inevitable to push the generalization up into higher parts of nature, rank over rank into sentient beings. Nations burn with internal fire of thought and affection, which wastes while it works. We shall find finer combustion and finer fuel. Intellect is a fire: rash and pitiless it melts this wonderful bone-house which is called man. Genius even, as it is the greatest good, is the greatest harm. Whilst all thus burns,--the universe in a blaze kindled from the torch of the sun,--it needs a perpetual tempering, a phlegm, a sleep, atmospheres of azote, deluges of water, to check the fury of the conflagration; a hoarding to check the spending; a centripetence equal to the centrifugence: and this is invariably supplied. The railroad dirt-cars are good excavators; but there is no porter like Gravitation, who will bring down any weights which man cannot carry, and if he wants aid, knows where to find his fellow-laborers. Water works in masses, and sets its irresistible shoulder to your mills or your ships, or transports vast boulders of rock in its iceberg a thousand miles. But its far greater power depends on its talent of becoming little, and entering the smallest holes and pores. By this agency, carrying in solution elements needful to every plant, the vegetable world exists.