timbers and the wainscoting of the house in which we live in order to boil our mess of pottage."
Physical effects
The indirect effects of these changes are fully as great as the direct ones. Forests greatly affect climate, temperature, and soil; they influence the humidity. They equalize the flow of streams, moderate floods, and by preventing the washing down of the rich soil, keep the mountain sides from becoming bare and sterile rocks. So, within the last two decades, the people in America have begun to think of forestry. Its purpose is to restore the forests to the condition of permanent rent-earners, to make the mountains yield not a temporary supply, but a perpetual crop of timber.
Possible exhaustion of the coal-supply
2. The extraction of coal and other mineral deposits reduces for future generations a supply already limited. The coal deposits in the earth have only recently been drawn upon. A small city like Ithaca probably uses to-day a greater quantity of coal than was used in all Europe two centuries ago. The large deposits of coal and their early development in England long gave a great advantage to English industry over that of other countries. In England, however, has first been felt the fear of the exhaustion of the coal-supply. Professor Jevons, in 1861, sounded the note of alarm; he prophesied that because the coal deposits of America were many times as great as those of England, industrial supremacy must inevitably pass to America. Already the supremacy in coal and iron production has passed to America, and that in textiles soon will come. In England the accessible supply of coal is limited, deeper shafts must be sunk, and the coal gotten with greater difficulty and at greater expense. Coal has risen in price in England within the last few years, and will continue to rise in the future. The coal deposits of America are thirty-seven times as great as those of England, but even these will soon be exhausted. And yet on the part of all except the coal trust, there appears in America a thoughtless disregard for the future. Supplies of copper, iron, and lead in favored positions are likewise limited, and are being rapidly centered in the hands of great companies. The increasing demand for these products insures a steadily rising income from their annual use. The value of the mines, being based on the series of incomes they will yield, may increase while their unused treasures dwindle in quantity.
Many natural resources are being rapidly exhausted
3. The exhaustion of natural stores of material is due to civilization, but it threatens to put an end to industrial progress. The savage does not go deep enough to use up permanently the world in which he lives. He uses the fruits that he finds, and those fruits are, almost without exception, renewed the next year. The only mines that were worked out in ancient times were gold and silver mines, while the mines of useful metals were touched but lightly. Within the last century the earth's crust has been exploited with startling rapidity. Scientific knowledge and mechanical improvement have combined to unlock the storehouses of the geologic ages. At the ever-increasing rate of their use, many important materials must be exhausted in the not far distant future. While it is probable that substitutes will be discovered for many of them, the outlook in some directions has little promise. To treat terminable incomes, exhaustible sources of supply, as permanent sources of income, leads alike to unsound theory and to reckless practice.
CHAPTER 12
INCREASE OF RENT-BEARERS AND OF RENTS
§ I. EFFORTS OF MEN TO INCREASE PRODUCTS AND RENT-BEARERS
Desire for better agents impels men to improvements
1. While man destroys some agents of production he multiplies many others. We have noted many kinds of depreciation, destruction, and wearing out of wealth; but the normal thing in a healthy society is an increase, on the whole, of rent-bearers. The increase of rents is due to two causes: changes in the agents by which they become more efficient technically, or more numerous; and changes taking place outside of the agents, affecting the utility of the products. The first of these will be considered in this section.
The increase of the efficiency of agents is usually the aim of the individual producer, and thus is brought about an increase of the stock of wealth. In some cases, however, improvements such as the dredging of harbors or as the protecting of forests, are made by men collectively through the agency of governments. Somewhere, however, the desire for these changes must arise in the minds of individuals. Increase of most things involves "cost" or sacrifice, in the psychological sense; that is, man must strive, perhaps suffer, to get a certain result. This end, therefore, must be in itself desirable, and social organization must be such as to present a motive to the men to make the needed effort.
Improvements by adaptation of natural resources
2. Rent-bearers may be increased in quantity and improved in quality by the adaptation of natural resources to man's purposes. To get food, men use the tracts of land that under the conditions give the largest product. Other tracts less fertile, or for some reason less available, are ditched, tiled, and diked, and fertilizers are carried up steep hillsides to make a soil upon the very crags. In commerce and transportation, new ways are opened by canals, railroads, and tunnels. An isthmian canal will raise the efficiency of ships plying between New York and San Francisco, enabling them to carry a greater amount of freight within a year. The tolls will represent to the users an expenditure only partially offsetting the increased efficiency of the agents of transportation. By the building of wharves, the dredging of harbors, and by many other methods, indirect agents are constantly growing in number and efficiency.
Machinery is an adaptation of natural resources
3. Rent-bearers may be increased by inventions and improvements that make machines stronger, quicker, and better. This proposition is not logically different from the preceding. A machine is an arrangement of material things through which force may be indirectly applied to move matter. No fast line divides machinery as regards form, purpose, or cause of value, from the artificially improved natural agents that we have been discussing. Just as a field is drained, plowed, and cultivated to fit it better to yield a crop, so is the iron ore shaped into a form called a machine, better fitted to cut, carve, and weave as man wills. Machines are merely adaptations of natural resources.
Bettering quality of agents
Increase in machinery may be either in quality or quantity. The two causes have in most cases the same result. If the quality or efficiency of looms is doubled, it is as if their number had grown in like proportion. In its economic function the beast of burden may not illogically be classed with inanimate machines. The horses in America have been remarkably improved of recent years by the importation of thoroughbred stock from Europe. Ten or fifteen years ago the number of horses in the United States was found to have decreased, and there was much comment on this evidence of a declining industry. It was not at once recognized that there was embodied in horse-flesh more horse-power than ever before, as a single Norman horse has the strength of several Mexican mustangs. Numbers alone are not the measure of efficiency.
Increasing number and better grouping of agents
4. The increase of wealth and the betterment of environment go on as well through the increase in the number of appliances and through their improved arrangement, as through changes in their kind. A machine is an adjustment of various natural agents to each other so as to make a more efficient agent, and machines in turn may be adjusted as parts of a larger system of production. The ideal of the modern factory
