Glucose is employed in the cheaper kinds of confectionery in the United States; most of it, however, is exported to Great Britain, the annual product being worth about four million dollars. From the fact that it can be made more economically from corn than from any other grain, practically all the glucose is made in the United States. QUESTIONS FOR DISCUSSION It frequently happens that the prices of sugar and tin-plate rise and fall together; show how the fruit-crop may cause this fluctuation. Which of the possessions of the United States are adaptable for cane-sugar?--for beet-sugar? In what ways has the manufacture of sugar brought about international complications? What is meant by "Dutch Standard" tests?--by polariscope tests? FOR REFERENCE AND STUDY Obtain specimens of rock candy, granulated sugar, raw sugar, and caramel; observe each carefully with a magnifying glass and note the difference. World's Sugar Production. CHAPTER XV FORESTS AND FOREST PRODUCTS Outside the food-stuffs, probably no other material is more generally used by human beings than the products of the forests. More people are sheltered by wooden dwellings than by those of brick or stone, and more people are warmed by wood fires than by coal. Even in steam-making a considerable power is still produced by the use of wood for fuel. Neither stone nor metal can wholly take the place of wood as a building material; indeed, for interior fittings, finishings, and furniture, no artificial substitute has yet been found that is acceptable. For such purposes it is carried to the interior of continents and transported across the oceans; and although the cost has enormously increased, the demand has scarcely fallen off. =Forest Areas.=--The great belts of forests girdle the land surface of the earth. A zone of tropical forest forms a broad belt on each side of the equator, but mainly north of it. This forest includes most of the ornamental woods, such as mahogany, ebony, rosewood, sandal-wood, etc. It also includes the most useful teak as well as the rubber-tree and the cinchona. Another forest belt in the north temperate zone is situated mainly between the thirty-fifth and fiftieth parallels. It traverses middle and northern Europe and the northern United States. This forest contains the various species of pine, cedar, and other conifers, the oaks, maples, elms, birches, etc. Most of the forests of western Europe have been greatly depleted, though those of Norway and Sweden are still productive. The forests of the United States, extending from Maine to Dakota, have been so wellnigh exhausted that by 1950 only a very little good lumber-making timber will be left.