Alice wants some india-rubber shoes. Do you think the kingdoms of air and water can send her a pair? The india-rubber tree in South America will take up water, and separate from it hydrogen, of which it is partly composed, and adding to this carbon from the air, will make a gum which we can work into shoes and balls, buttons, tubes, cups, cloth, and a hundred other useful articles. Then, again, you and I, all of us, must go to the world of gases for nitrogen to help build our bodies, to make muscle and blood and skin and hair; and so the peas and beans load their boat-shaped seeds full, and bring it to us so fresh and excellent that we enjoy eating it. This useful carrying trade has also another branch well worth looking at. You remember hearing how many soldiers were sick in war-time at the South; but perhaps you do not know that their best medicine was brought to them by a South-American tree, that gathered up from the earth and air bitter juices to make what we call quinine. Then there is camphor, which I am sure you have all seen, sent by the East-Indian camphor-tree to cure you when you are sick; and gum-arabic and all the other gums; and castor-oil and most of the other medicines that you don't at all like,--all brought to us by the plants. I might tell you a great deal more of this, but I will only stop to show a little what we give back in payment for all that is brought. When England sends us hardware and woollen goods, she expects us to repay her with cotton and sugar, that are just as valuable to us as hardware and woolens to her; but see how differently we treat the kingdoms from which the plant-ships are all the time bringing us food and clothes and medicines, etc. All we return is just so much as we don't want to use. We take in good fresh air, and breathe out impure and bad. We throw back to the earth whatever will not nourish and strengthen us; and yet no complaint comes from the faithful plants. Do you wonder? I will let you into the secret of this. The truth is, that what is worthless to us is really just the food they need; and they don't at all know how little we value it ourselves. It is like the Chinese, of whom we might buy rice or silk or tea, and pay them in rats which we are glad to be rid of, while they consider them good food. Now, I have given you only a peep into this carrying trade, but it is enough to show you how to use your own eyes to learn more about it. Look about you, and see if you can't tell as good a story as I have done, or a better one if you please. CHAPTER I. THE STAR-FISH TAKES A SUMMER JOURNEY.