. Le jardin du débutant livre ; un manuel pour la partie supérieure de la grammaire. Le jardinage. 98 LE JARDIN DU DÉBUTANT LIVRE. La question qui reste d'un végétal après ce séchage complet est principalement composé de carbone de certains. Nous savons mieux que le carbone que le charbon ; mais quand il est cristallisé le dia- mond, ou l'exemple de nos crayons ; et lorsqu'il est combiné avec d'autres éléments qu'il prend diverses formes, le chef de ce qui dans les plantes est l'amidon. Enfin, en plus d'eau et de carbone, le plus important des produits chimiques dans les plantes sont le phosphore, la potasse et l'azote. Ces derniers, au moins, sont les éléments qu'il est le plus important pour nous

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. The beginner's garden book; a textbook for the upper grammar grades. Gardening. 98 THE BEGINNER'S GARDEN BOOK. The matter which remains from a plant after this thorough drying is chiefly some compound of carbon. Carbon we know best as charcoal; but when crystallized it is the dia- mond, or the lead of our pencils; and when combined with other elements it takes various forms, the chief of which in plants is starch. Finally, besides water and carbon, the most important chemicals in plants are phosphorus, potash, and nitrogen. These, at least, are the elements which it is most important for us to supply, since they are the elements with- out which plants suffer. We studied in the last chapter how to save water for the use of our plants. Carbon we do not need to trouble about, for the very good reason that plants get most of their carbon from the air. The amount of carbon in any given amount of air is so small that I did not mention it just now when telling what air was com- posed of. In ten thousand parts of air there are but one and a third parts of carbon; yet so vast is the amount of air over the earth, and so rapidly does it change among the leaves of the plants, that it supplies most of the carbon for all the plants that grow on the earth. The other three elements we must supply. But first it may be asked why we have to take pains to supply plants with any food. Truly, in wildernesses no food is supplied by man. The forests grow, and maintain themselves for centuries; year after year the swamps grow rank with grasses. But this is because that which dies lies and rots on the ground, return- ing to it the food which once it took up. Even when man comes into the forest and takes away logs, he leaves more than Fig. 55. — The chemical make-up of a potato. 1 repre- sents water; 2, starch; 3, nitro- gen; 4, all other elements.. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and a

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