§ 7. Using up of agricultural land. Even land, which men are prone to think of as everlasting, is in some of its most im portant uses subject to constant wear and loss of its valuable qualities. In agriculture the land furnishes not only standing room and a surface exposed to air, sun, and rain, but a store of materials fitted to nourish vegetation. Under the proper conditions of heat, moisture, and texture of soil, the plants, through the aid of bacteria, select and take up partly from the air but mostly from the soil, the chemical elements needed for their growth. Cultivation of the soil is regrouping and collecting the fertile elements, but harvesting the crop is ex tracting them from the soil. This process can not be continued indefinitely unless these elements are restored to the land. The barbarian lacked the forethought and patience to preserve the land, and his methods of agriculture used up the soil. After a few years he moved on, burned and cleared out another little space in the midst of the forest. The progress of men toward a settled life and a permanent agriculture has been accom panied step by step by the introduction of conservative (dura tive) methods of using the arable land. The temptation to revert to improvident methods has again and again shown itself as a result of the demoralization of war, of invasion by less advanced peoples, or of the opening of great areas of new § 8. Artificial durability of agricultural land. When a method of permanent agriculture has become firmly established in a community, guarded by ancient customs and by very care ful contracts between tenants and landlords, agricultural es tates, as wholes, are given artificially an appearance of great durativeness, altho the land, excepting as bare surface, is being repaired and remade continuously. The uses of the farm are estimated as a net sum, after deducting the cost of all the re pairs. Agricultural land has constituted in western Europe in recent centuries the most permanent body of wealth, and thus it came to be looked upon mistakenly as a most perfect type of durative goods. Land-sites for residence and business uses, merely as standing room, are in most locations among the most durative of all forms of wealth ; on the contrary, mineral deposits constitute a strikingly consumptive form of use-bearer.
§ 9. Varying rates of depreciation of machinery. There is a great difference in the length of the economic life of manu facturing appliances. The building is fairly durable; yet in good business practice an average depreciation-rate of per cent a year is allowed to offset a reduction in its value of over 50 per cent in thirty years, after providing insurance against the chance of loss by fire. Machinery differs greatly in durability ; well-made, substantial machinery depreciates about 5 per cent yearly. The engines and boilers depreciate 1 See ch. 36 for further remarks on the destruction and conservation of farm lands.
more rapidly than the running gear; the loose tools have to be replaced every second to fourth year; while the materials consumed in the industry must be repaired and replaced at every repetition of the process of manufacture. If a factory is to be maintained in its efficiency in a way to afford its owner a continuing income, everything about it must be from time to time repaired and replaced.
§ 10. Repair of tools and machinery. Separate tools are dependent for their usefulness on substance and form, and they gradually undergo changes which consume them—by decay, rust, wear, breakage, etc. They thus as a class are looked upon
as consumptive agents. Yet the whole groups, the parts of which can be separately repaired, may be given artificially a laige measure of durativeness.
The railway unites in a large degree the use of land surface with that of durable forms of metals. The roadbed, which is but the natural surface excavated or filled to a more suitable grade, is the most permanent part; yet every frost weakens, every rain undermines, a portion of it. Earthquake, land slide, and flood fill up the ditches, or tear down the embank ments. Constant work is needed to keep it fit and safe for use. On the roadbed is the track, slightly less permanent, more frequently changed. The ties rot, and even the steel rails must be replaced in twenty or thirty years. The rolling stock is still less durable, and the different parts vary in length of life. It is said that the wheel-tires of a locomotive are re newed four times, the boiler three times, and the paint seven times, before the machine as a whole is rejected as entirely worn out. The oil used on the bearings, which is a necessary part of the running machine, has to be applied every day.
§ 11. Economy of repairs. In general the maintenance of repairs in durative agents is a large part of the practical art of the business manager, whether husbandmen or artizan. It is an art calling for as much judgment and skill as does any part of the management. The neglect of repairs may have different results in the different parts of the enterprise. Fail ure to replace separate, worn-out tools, while not preventing the future restoration of the plant to its full efficiency, causes the factory as a whole to be less efficient. Each part of the entire outfit being needed in due proportion,' the want of any one tool causes a loss of the efficiency of the factory as a whole disproportionate to the missing tools. Failure to apply seed to the land causes the land as a whole to be useless for that year's crop. The seed is a necessary part of the productive field, considered as a unit, and its annual application is closely analogous to repairs. In other cases, neglect of repairs in creases the expense of repairs and cuts of future incomes. The adages, "A stitch in time saves nine," and "An ounce of prevention is worth a pound of cure," must be acted upon in every industry. The neglect to repair a roof causes damage to an amount many times the cost of a new roof. Failure to replace a bolt costing five cents may result in the rack and ruin of a machine worth many dollars. A handful of earth on a dike may save a whole country from destruction. In every business that is to be continued it is true that neglect or postponement of repairs causes a falling off of the value of the uses, usually far outweighing the temporary saving in cost .a Neglect of repairs may be economical, however, when indus trial changes have first reduced the demand for the agent and consequently the value of its uses. When the line of travel changes, it does not pay to keep an old hotel up to the same state of repair as when it had a great patronage. Old factories sometimes may better be allowed to depreciate, while the price of repairs is invested in more prosperous industries. In a de clining neighborhood the houses fall into decay, the owners seeing that "it would not pay" to keep them up.