Now, in general, when such rents appear, they may be capitalized. And the price of the instrument of production that bears these rents, will be the sum of the rents, discounted at the prevailing rate of interest, with considerations of risk, etc., allowed for. The reasoning of the capitalization theory is really quite simple. Take, for example, a piece of urban site land, which is expected to bring a perpetual annuity of one hundred dollars. The whole economic significance of the land is contained in its services, present and prospective. The possession of land under certain circumstances brings other services, as social prestige, than the services which can be alienated to a lessee. But in this case I am abstracting from considerations of that sort, and also from the factor of risk. The whole value of the piece of land under consideration comes from the value of the one hundred dollars a year. But these annual incomes are not all equally valuable, even though all expressed as one hundred dollars. The first one hundred dollars is due one year hence, the tenth ten years hence, the thousandth, a thousand years hence. The principle of perspective comes in--I abstain from any detailed discussion of the theory of interest, simply stating that in a general way I agree with the contention that _time_ constitutes the essence of the phenomenon, or rather, the tendency to discount the future. The capital price of the land is the sum of an infinite convergent series of the "present worths" of the incomes. The formula is as follows: capital price of land = $100/1.05 + $100/(1.05)^2 + $100/(1.05)^3 ... + $100/(1.05)^n when the rate of interest is 5%. The limit of this series, assuming the series to be infinite, is $2000, and a simple formula for calculating it under the assumptions, is to divide $100, the annual income, by .05, the rate of interest. Given the annual income, given the prevailing rate of interest, the capital price is determined. The relation may be illustrated, roughly, by the figure of a candle, a disk, and the shadow of the disk on the wall. The disk represents the annual income, the shadow on the wall the capital value, and the distance between the flame and the disk the rate of interest. Increase the distance between the flame and the disk, the rate of interest, and the shadow becomes smaller; shorten the distance, and the shadow is increased. Similarly, enlarge the disk, and the shadow is enlarged. The capital value varies directly with the annual income, and inversely with the rate of discount. Now my purpose here does not involve a detailed examination of the validity or limitations of the capitalization theory. For the present, the only question is, has this theory any application at all to the problem of the value of money? It offers itself as a general theory of the values of durable bearers of income. Money is a durable bearer of income.