vent loss. This extra labor in harvest time is usually supplied by the wives and children of the laborers. The harvest season extends over a period of about four months, beginning August 15 to September 10, according to locality.

"Cotton is probably a native of the tropical and semi-tropical regions of both hemispheres. The earliest records of the Asiatics and Egyptians speak of it; Columbus found it growing abundantly in the West Indies, while other early explorers found it growing in Mexico and South America. . . . There is no region in the world which has such a favorable combination of suitable land, intelligent and plentiful labor, cheap capital and adequate transportation facilities for the cultivation of cotton as the cotton belt of the United States. It has been the chief source of supply of the cotton mills of the world, for in this section has been raised several times the quantity of cotton produced in all other countries of the globe. There are various other countries which seem to possess the soil and climatic requirements for its growth, but for various economic reasons the industry has not been greatly developed in them; however, a considerable quantity is produced in the following countries in the order named: India, Egypt, China, Italy, Turkey, Brazil, West Indies, Mexico, South America, Australia, and the South Sea Islands."

140. Further study of fiber-producing plants. -Study No. 60. (Optional.) Select one or more of the following fiber-producing plants for further study: flax, hemp, jute, raffia, hat-straw. Consult Bailey's "Cyclopedia of American Agriculture," Vol. II," Crops,” or any encyclopedia. Determine (1) the parts of the United States (or of the world) in which the crop is raised in large quantity, (2) the amount and value of a year's crop, (3) methods of harvesting and preparing the crop for market.

II. THE USES OF FORESTS AND FOREST CONSERVATION

141. Uses of forests for fuel, lumber, and other commercial purposes. In the earlier days of our country's history all the fuel for heating, for running locomotives and other en

gines was supplied from the forests. About one hundred and fifty years ago, coal was discovered in Pennsylvania, and one would suppose that since that time our forests would have been drawn upon less heavily for fuel. But it is estimated that the United States burns annually at the present time one hundred million cords of wood. While we are considering the uses of plants as fuel, we should remember that our

enormous coal beds were without doubt formed from great tree ferns and other plants which lived in bygone ages. Petroleum, too, from which our kerosene oil is produced, is believed to be a product of plant decomposition.

One has but to call to mind the enormous use of trees for framing and finishing houses, for furniture, for railroad ties, telephone and telegraph poles, for shipbuilding, and for boxes, barrels, and paper manufacture, to realize how seem

ingly indispensable are forests. When the early settlers reached this country, they found a virgin forest covering the whole land. Their first work was to clear land in order to get open spaces for cultivation and as a means of protection from attacks of the Indians. They cut down the trees ruthlessly and the timber and wood which was not needed was left to decay or become the prey of forest fires. This forest de

struction has continued even to our own day. But at last men are beginning to see that unless this slaughter of our trees is stopped, our timber supply will soon be gone. In fact, government experts tell us that if the tree areas that yet remain are not managed according to a different system, twenty years hence we shall reach the end of the timber supply in the United States.

142. Further study of forest products. - Study No. 61. (Optional.) Select one or more of the following forest products for fur

ther study: maple sugar, rubber, tar, turpentine, wood pulp, alcohol, charcoal. Consult Bailey's "Cyclopedia of American Agriculture," Vol. II, "Crops," or any encyclopedia. Determine (1) the parts of the United States (or of the world) in which the product is obtained in large quantity, (2) the amount and value of a year's crop, (3) methods of preparing the product for market.

143. Uses of forests in regulating rainfall and flow of streams. We turn now from a consideration of our forests as a source of lumber and manufactured products to a discussion of their effect on the fall of rain and the flow of streams. It is probably true, in the first place, that the destruction of large tracts of forest lands means a lessened rainfall, at least so far as local showers are concerned. We saw in our study of the functions of the nutritive organs of a plant that great quantities of water are absorbed by the roots, carried up through the woody bundles of the stem, and given off through the stomata of leaves. It has been estimated that a single oak tree of average size gives off in a single season over one hundred and twenty-five tons of water. If we were to multiply this amount by the number of trees in a forest, we would get some idea of the enormous amount of water lifted into the air by this agency.

Not only do trees help to produce rain; they also conserve the rain when it falls by holding it in the soil, and preventing disastrous floods. Let us see how this is brought about. When the raindrops fall upon the tree tops, the water drips from leaf to leaf, and finally reaches the ground. Here it trickles down through the floor of the forest, which is formed of thick layers of decaying leaves, interlacing roots, and earth particles (see frontispiece). All these form a porous sponge which absorbs and holds back the water. Suppose, now, the trees are removed from the hillsides. When the rains come, there is no means of absorbing the water; instead, it flows