Thus water quenches, not only the thirst of men, but likewise of arid lands: and He who gave us that fluid body has carefully distributed it throughout the earth, like pipes in a garden. The waters fall from the tops of mountains where their reservatories are placed. They gather into rivulets in the bottom of valleys. Rivers run in winding streams through vast tracts of land, the better to water them; and, at last, they precipitate themselves into the sea, in order to make it the centre of commerce for all nations. That ocean, which seems to be placed in the midst of lands, to make an eternal separation between them, is, on the contrary, the common rendezvous of all the people of the earth, who could not go by land from one end of the world to the other without infinite fatigue, tedious journeys, and numberless dangers. It is by that trackless road, across the bottomless deep, that the whole world shakes hands with the new; and that the new supplies the old with so many conveniences and riches. The waters, distributed with so much art, circulate in the earth, just as the blood does in a man's body. But besides this perpetual circulation of the water, there is besides the flux and reflux of the sea. Let us not inquire into the causes of so mysterious an effect. What is certain is that the tide carries, or brings us back to certain places, at precise hours. Who is it that makes it withdraw, and then come back with so much regularity? A little more or less motion in that fluid mass would disorder all nature; for a little more motion in a tide or flood would drown whole kingdoms. Who is it that knew how to take such exact measures in immense bodies? Who is it that knew so well how to keep a just medium between too much and too little? What hand has set to the sea the unmovable boundary it must respect through the series of all ages by telling it: There, thy proud waves shall come and break? But these waters so fluid become, on a sudden, during the winter, as hard as rocks. The summits of high mountains have, even at all times, ice and snow, which are the springs of rivers, and soaking pasture-grounds render them more fertile. Here waters are sweet to quench the thirst of man; there they are briny, and yield a salt that seasons our meat, and makes it incorruptible. In fine, if I lift up my eyes, I perceive in the clouds that fly above us a sort of hanging seas that serve to temper the air, break the fiery rays of the sun, and water the earth when it is too dry. What hand was able to hang over our heads those great reservatories of waters? What hand takes care never to let them fall but in moderate showers? SECT. XIV. Of the Air.