GROUND RENT A SOCIAL PRODUCT 13 Ground rent may be said to result from at least three distinct causes, all connected with aggregated social activity: (1) Public expenditure: All wise public expenditures are direct feeders of ground rent. Streets, lights, water, sewerage, fire and police systems, public schools, libraries, museums, parks and play grounds, all contribute to enhance the value of land, and a corresponding depreciation would follow the abolition of any of these systems. It follows, there fore, that expenditure for maintaining these services constitutes the maintenance of ground rent, if not in a literal sense, at least in an all-sufficient common sense. (2) Quasi-public expenditure; In the same way, the expenditure by the municipality or by private corporations for steam and electric railways, gas and electric lights, telegraph and telephone facilities, subways and ferries, contributes to the value of land, at least to the extent of their actual cost. (3) Private expenditure; Equally, and by parity of reasoning, private or voluntary social expenditure for churches, private schools, colleges and universities, all private buildings, apartment houses, stores, and office buildings, contributes to ground rent, the annual value of land. In an enumeration of the causes of ground rent, population is usually the one first named. But a passive population gives little value to land; it is rather the activities consequent upon the character population that create the value. It is generally conceded that, as a matter of fact, ground rent is what land is worth annually for use;