“Remember, too, what happens after watering the garden. When, at close of a very warm day, we have to give a drink to those poor plants dying of thirst, something like this happens: The pump runs at its utmost capacity; you all make haste with your watering-pots; one goes here, another there, carrying water to the suffering plants, seed-plots, and potted flowers. Soon the garden has drunk copiously. How fresh it is then, how the plants, wilted by the heat, regain vigor and straighten up again, as happy as ever! You could almost think you heard them whispering to one another and telling how glad they were to be watered. If it could only stay that way! But, bah! the next day the earth is dry once more and all has to be done over again. What has become of the last evening’s water? It has evaporated, dissolved into the air; and now it is perhaps traveling far away, at a great height, until, turned into a scrap of cloud, it falls again in rain. When Jules tires himself working the pump to water the flowers, has he ever thought that the water drawn from the well and spread over the ground sooner or later is dissipated in the immensities of the air to play its modest part in the formation of clouds?” “In watering my garden,” answered Jules, “I did not think I was watering the air more than anything else. But I see now: air is the great drinker. Of the contents of a watering-pot the plants take perhaps a handful; the air drinks up the rest. And that is why we have to do it all over again every day.” “And if you exposed a plateful of water to the sun what would finally become of it?” “I will answer that,” Emile hastened to reply. “Little by little, the water would turn into invisible vapor and there would be nothing but the plate left.” “What takes place at the expense of a plate of water, and of the moisture of the soil or wet linen, takes place also, on a vast scale, over the entire surface of the earth. The air is in contact with damp soil, with innumerable sheets of water, lakes, marshes, streams, rivers, brooks, above all with the sea, the immense sea, which presents thrice as much surface as the dry land. The great drinker, as Jules calls it, the air, must therefore drink to satiety and everywhere and always contain moisture, sometimes more, sometimes less, according to the heat. “The air that is around us now, that invisible air in which the eye distinguishes nothing, nevertheless contains water that can be made visible. The means is very simple; all that is necessary is to cool the air a little. When you squeeze a wet sponge with the hand, you make water ooze out of it. Cold acts on moist air very much as the pressure of the hand on the sponge: it causes the moisture to distil in the form of minute drops. If Claire will go to the pump and fill a bottle with very cold water, I will show you this curious experiment.”