likewise, on the sea coast or on large rivers, may water carriage: though the wharfage or harbour-room applicable to the service of that mode of transport is in many situations far short of what would be used if easily attainable.
It will be seen hereafter how much of the economy of society depends on the limited quantity in which some of the most important natural agents exist, and more particularly land. For the present I shall only remark that so long as the quantity of a natural agent is practically unlimited, it cannot, unless susceptible of artificial monopoly, bear any value in the market, since no one will give anything for what can be obtained gratis. But as soon as a limitation becomes practically operative; as soon as there is not so much of the thing to be had, as would be appropriated and used if it could be obtained for asking; the ownership or use of the natural agent acquires an exchangeable value. When more water power is wanted in a particular district, than there are falls of water to supply it, persons will give an equivalent for the use of a fall of water. When there is more land wanted for cultivation than a place possesses, or than it possesses of a certain quality and certain advantages of situation, land of that quality and situation may be sold for a price, or let for an annual rent. This subject will hereafter be discussed at length; but it is often useful to anticipate, by a brief suggestion, principles and deductions which we have not yet reached the place for exhibiting and illustrating fully.
