It germinates and makes a little growth before the ground freezes and snow comes. The green shoots may freeze, but the plant as a whole does not and is ready to take advantage of the first warm day of spring. As a result it completes its growth early and is ready for harvesting in early summer, long before the spring wheat.

Have you ever seen the beautiful, green fields of winter wheat? It is not the cold weather that harms the wheat so much as alternate thawing and freezing. We can comfort ourselves, when the winter is a hard one and there is a great deal of snow, with the thought that the wheat is safely covered, and is likely to give us a good harvest.

Oats do not require so rich a soil as wheat (see § 159). The seed is planted in early spring. Oats, like wheat, grow better in a cool climate. For what is the oats crop used principally? Do people use oats? Look up the composition of oats in Appendix, Table IV. Do they have a high food value? Rye has winter and spring varieties, much as wheat has. Barley, like rye and oats, is used as a substitute for wheat when wheat is scarce.

315. How Do Corn and Rice Grow? Corn, as we have seen (see § 313), is a native grass of America, and was known to the Indians and grown by them as a food crop long before America was known to the white man. It is grown in almost all parts of our country, but there is a region of the Middle West called the "corn belt," where it is the principal crop. Where is the corn belt? In Europe corn does not grow so well as in America, hence what corn is used there is largely imported from this country. What is the chief use of corn?

Name some of the different kinds of corn. Of course you will include sweet corn, which has a good deal of sugar in it, and pop corn (see § 195). The two principal kinds of field corn" are known as

66

flint corn and dent " " corn. The flint corn gets its name from. the fact that it is hard and translucent, like flint; generally it is best for a region where the summer is short, as it ripens very quickly. Dent corn is soft and has a larger grain with a dent at the top of the grain. It often grows to a great height: 16 or 20 feet; but it some

FIG. 241.

(Reproduced by permission of the Philadelphia Commercial Museum.)

- A field of rice planted in flooded ground.

times requires five or six months to ripen properly. Find out what products are made from corn. Do you know any boy or girl who has learned how to judge the quality of corn? Is pop corn more like a flint corn or a dent corn?

Rice (Fig. 241) belongs to the grass family, but it differs from other members in beginning its life as a water plant. It is planted in flooded land and needs a soil that remains very moist. It is a native of the East Indies, and is the

principal food of the peoples of Asia, or of one half of the human race. In our own country rice is an important

crop of the South

ern States. Look

up the food value

of rice in Appen

(Reproduced by permission of the
Philadelphia Commercial Museum.)

FIG. 242. How the juice of the sugar cane is
crushed out of the stalk.

our Gulf States; a great deal is grown also in Cuba, Java, the Philippines, and Hawaii. The cane forms a large grass with a solid stem. In order to get the sugary sap out of the stems, men crush them (Fig. 242) between rollers, or grinders; the sap is then boiled down to get the sugar to crystallize out (see § 118).

The sugar obtained by this first crystallization is brown sugar, colored by some of the other materials of the sugar cane. The sticky liquid from which the sugar crystallizes out is molasses. To purify, or refine, the brown sugar, men dissolve it again in water, and filter the water solution (see § 139) through a filter of charcoal. The charcoal removes the dark color of the brown sugar solution, and when the solution is boiled down once more, the sugar which crystallizes out is our familiar white sugar. The solution from which the refined sugar separates is sirup. You would not think that black charcoal could take dark colors out of sugar solutions, but it is so. Sugar is a definite substance (see § 110), and is found in other plants besides the sugar cane. In Europe most of the sugar is obtained from sugar

beets.

Have you ever used a bamboo fishing pole? It probably came from the South, and is a small kind of bamboo that grows in the canebrakes. The real bamboo grows in Asia, and is of the greatest importance to the people. Some kinds of bamboo reach a height of 100 feet and are a foot in diameter. You can see that such great stalks could be used for building bridges and houses, for water pipes, rain troughs, and fences; and this is just what the people do with them. They also use bamboo in split form and weave from it baskets, mats, and screens. In fact, it largely takes the place of wood and of metals.

317. Why Is Wheat Used for Bread? Have you ever wondered why, with so many grains, such as barley, rye, oats, rice, and corn to choose from, our people should insist on using wheat for their yeast bread? In the countries of Europe, where wheat is difficult to grow, barley and rye breads have been used for centuries instead of wheat breads. Do you remember the experiment

we carried out in § 190, in which we separated the starch of wheat flour from the gluten? Review this experiment. Gluten is good not only because it furnishes us nitrogen in our bread, but because it is sticky, and holds the dough together. Now, when yeast ferments the bread, producing carbon dioxide (see §§ 201 and 202), it is necessary that the dough shall hold the carbon dioxide and prevent it from escaping until it has collected in a large amount. As we have learned, it is the gas bubbles that make the bread porous and light. Wheat has more gluten in it than any of the grains, and this is the reason it is so good for bread-making. Rye is next best in its amount of sticky material, and in spite of a darker color than wheat, makes a nutritious and wholesome bread. Breads can be made by proper methods from the other food grains, especially if their flours are mixed with a certain amount of wheat flour, or rye, so that they have the advantage of the large supply of sticky material found in the wheat and rye.

Wheat flour is the wheat grain ground to powder. If the seed coat, corresponding to the "skin" of the bean, is left with the flour, we have Graham flour; if the seed coat, and nothing else, is removed, we have whole wheat flour. The seed coat forms "bran." If the flour is "bolted," that is, sifted through very finely woven cloth, any bits of the seed coat that remain, and the darker, harder, outside portions of the grain are removed, and the flour is whiter. It has lost, however, some of the nutritious material found on the outside of the wheat grain.

Both winter and spring wheats have varieties known as hard" and "soft" wheats. Hard wheats are those with a great deal more gluten in them, and less starch, than the soft wheats. The maca