As the number of agents increases they are distributed so as to be where most useful to the owner. A man having two umbrellas keeps one at his office and the other at home; a student having two books of the same kind keeps one at his room and the other at the university; a farmer having two hoes keeps one at the barn and the other in a distant field, and by this distribution the agents are increased in efficiency. [Sidenote: A larger and better environment] The aim of a progressive society is to enlarge the environment, and constantly to adapt it better to the service of wants. This is done largely by mechanical agents, which capture the natural forces of the world, put them into the right place at the right time, and make them do the right thing, or which group and relate the materials of the world in the right ways. Some of the groupings in the chemical and physical world that do not fit man's purposes may be made to do so. The world in this way becomes more and more a great workshop, better and better adjusted to man's wants. [Sidenote: Increasing some rent-bearers reduces the rents of others] 5. _The betterment of the environment of society in some directions reduces the rent of other parts._ The wish of the individual is to raise his own rent-bearers in efficiency, but in doing that he affects the agents owned and controlled by others. The ideal from a social standpoint is to increase not rent but the welfare of society, and this is not always the ideal of individuals seeking their own interest. However, as the efficiency of some agents rises, it becomes unnecessary and unprofitable to use the less fertile fields; they cease to be rent-bearers, and the rent of the richer fields falls under the influence of the new supply of products. Some inventions suddenly increase the efficiency of free goods to such a degree that the less efficient rented agents are thrown out of use, and the margin of utilization is moved to a higher plane than it was on before. Improved types of machinery more or less rapidly displace the older, less efficient types, which, therefore, more or less completely lose their rent-bearing power long before they are physically worn out. When improvements in agriculture that are applicable to a considerable area of land take place, and the product thus is increased and cheapened, the poorer land is abandoned. Inventions and improvements thus gradually becoming common property, increase the free goods and free uses not bearing rent and open to every one. One who improves the quality of a machine or the economy of a process may thus unintentionally injure some of the owners of low-rent agents, while unintentionally increasing the welfare of the mass of men for whom the margin of utilization is thus lifted. § II. EFFECTS OF SOCIAL CHANGES IN RAISING THE RENTS OF INDIRECT AGENTS [Sidenote: Effect of decrease of the competing agents]