3. _Men seek to convert into marketable capital any increase of income in their wealth or business._ A man who invests a given capital sum in machines, buildings, and materials buys them, as others do, at prices that represent their usual, or market, earning power. If he succeeds exceptionally in his business, he makes the capital earn more than the rents on which it was capitalized. The same material wealth becomes worth more because of the reputation of his products, and therefore the trade-mark and good-will of the business can be capitalized. In this sense a good name can be sold, and is at least as much to be desired, even in a mercenary age, as great riches. Likewise, social changes, new needs, the growth of population, increase the net income of wealth, or the rents of a business. The basis of capital value is income, and whatever be its cause, political or economic, material income can and will be capitalized and added to the market value of the privilege, wealth, or industry on which the income is conditioned. [Sidenote: The capitalizing of franchises for public-service corporations] Notable cases of this sort arise in connection with public franchises. If a street-railway or a gas-company is given the exclusive right to operate in a given locality, any income above average interest on the investment is capitalized either in the higher price of the stock or in additional stock issued without the addition of any material to the plant. If the franchise is unlimited, the income may be capitalized as practically perpetual; if the franchise is limited, and is to expire in thirty or forty years, only the limited series of privileged incomes can ordinarily be capitalized. When, however, the managers are able to exert influence enough to have the franchise extended, and the investors believe in the skill of the managers and perhaps in their power to bribe the legislators, the value of the stock continues higher than it could usually be under a limited franchise. Such circumstances becloud the question whether the exceptional income arising under the franchise should go to the public or to the company. Granted, however, that the company is entitled to the income, the burden of proof is on those who object to the capitalizing of the income as is done in every other business. [Sidenote: Some difficulties in the capitalization of corporate incomes]