1. _Men seek to increase income by increasing capital._ Men may strive to increase their rents without expressing the rent-bearer in terms of capital. Peasant owners and small proprietors, toiling fondly on their little estates, seeking steadily a larger crop, a larger income, accomplish wonders in bringing waste land to a high state of cultivation. Working on the soil that is at once their livelihood and their home, they do not consciously reckon the value of the labor they are putting upon it. No money can buy that which to them is beyond price. But, in our money economy, efforts are largely directed toward the increase of the capital sum. Investment takes the form of putting in a sum of money in the hope of getting an income bearing a certain relation to it. The first thought is of the value of the wealth invested, which has been carefully measured and expressed in dollars and cents. Wealth looked at in the older way was valued for what it did immediately for its owner, for its concrete fruits; looked at in the modern way, it is valued as a marketable income-bearer readily convertible into a multitude of other forms. Thus investments come to be thought of in terms of general purchasing power, from which it is expected to realize an income of a given percentage. [Sidenote: Free goods of unlimited supply] [Sidenote: Beginning of scarcity of common materials] 2. _There are some classes of goods that can be increased without any noticeable increase in difficulty._ The extremest examples are undiminished goods such as air, sea-water, the water of large rivers. These are free goods because, however much is used, the supply is immediately renewed. But they are undiminished only in a relative sense and in reference to present need. The water in the Western rivers long flowed on, undiminished by the uses made of it. But progressing civilization required more water for cities, for mining, and for irrigation, and now states and corporations are going to law over these formerly undiminished free goods. Some kinds of goods are produced from such very common materials that it might seem possible, by the substitution of agents, to produce an unlimited supply. How can bricks be limited in number, being made as they are from one of the commonest materials on the earth's surface? But the largest clay banks are limited in size; a large proportion of the places where bricks are needed are not near a supply of clay of good quality; and after a brick-yard has been used for a time there is increasing difficulty in getting out the material. While, therefore, bricks are scarce and hard to get from the outset in some places, the scarcity grows more marked in many places at first well supplied. If materials are scarce in any degree, their continued use for one purpose increases their scarcity in all other uses. Economic goods are goods having value; value implies scarcity, and an increasing demand means inevitably a higher value at some point. This