Gross and net income
4. Income in the logical sense must be a net addition, but the term gross income is not without popular and practical meaning. Gross income is sometimes spoken of in the sense of total receipts, as the total of goods secured; net income is the remainder after deducting expenditures and after replacing the goods employed to secure the income. In order to produce some goods technically, men make use of other goods. While they are storing up a supply of wood or coal it may be looked upon as the income, but they may burn it to help grow hothouse plants. While they gather flowers with one hand, they destroy fuel with the other. Only the net increase in value can be accounted income in the second period. The goods that come into a man's possession in any period are of many sorts: to get some he has destroyed many previously existing goods; while to get others he has not needed to use up the accumulations of the past or to mortgage the future. The one kind is gross, the other net income.
Wealth and income
5. An income of consumption goods is a part of wealth, but not the whole of it. The consumption goods, the "present goods" at the moment available, are the essential part of wealth for the moment's enjoyment. The only essential and immediate conditions of a series of gratifications is a regular series of consumption goods. But many things existing which could be used to secure a gratification are not in fact treated as consumption goods. A crop of corn is not all income. In a time of famine it could be used, but seed-corn was saved from last year, and some must be kept for next year. This is a part of wealth, but not of "present goods" as we understand the term.
Some goods never can become enjoyable goods
Further, in the economic world there is much wealth that never can gratify any want directly; many forms of wealth never can be consumption goods. It is true that everything called wealth is expected to contribute sooner or later in some way to the sum of gratifications. It is for that reason it is called wealth. It is, however, a mere figure of speech to say indirect want-gratifiers become want-gratifying goods. For example, the engine transporting a load of coal is indirectly gratifying wants; if it is transporting a train-load of passengers, the gratification is direct. A machine making cloth for next year is gratifying wants only in a metaphorical sense. A field used to produce food is not a direct want-gratifier until it is transformed into a residence site, a playground, or a tennis-court.
It is necessary therefore to recognize the distinction between present and future incomes. The value of the mass of wealth in possession and yielding income, rests in large part upon its power of contributing to income in some future period. Thus, any durable good may be looked upon as embodying a series of incomes ranging from present to future in varying degrees. This will be fully considered under the subject of capital.
Income from wealth and from labor
6. Incomes are called funded or unfunded according to the sources from which they are derived. Funded income arises from the possession of wealth or of claims on wealth, such as lands, railroad stocks, government bonds, etc. The income is "funded" because it corresponds to an abiding fund of wealth. The income arising from current labor is unfunded, because there is no permanent fund of accumulated wealth corresponding to it.
The idea of regularity connected with funded income is not essential to the idea of income in general, i.e., we cannot refuse to call a thing income because it occurs only this year. If it is part of the sum of goods that flows in, that is newly available for the man's use, it is income. But funded income is the more abiding, for income from wages stops when the man dies or fails to perform his work, while the income from wealth continues after he ceases to be active. Thus, families with equal incomes may differ greatly in wealth, the one depending entirely on salaries, the other on rents.