exposed either by the general circumstances of society or by the hazards of the particular employment, there remains a surplus, which partly goes to repay the owner of the capital for his abstinence, and partly the employer of it for his time and trouble. How much goes to the one and how much to the other is shown by the amount of the remuneration which, when the two functions are separated, the owner of capital can obtain from the employer for its use. This is evidently a question of demand and supply. Nor have demand and supply any different meaning or effect in this case from what they have in all others. The rate of interest will be such as to equalize the demand for loans with the supply [pg 441] of them. It will be such that, exactly as much as some people are desirous to borrow at that rate, others shall be willing to lend. If there is more offered than demanded, interest will fall; if more is demanded than offered, it will rise; and in both cases, to the point at which the equation of supply and demand is re-established.
The desire to borrow and the willingness to lend are more or less influenced by every circumstance which affects the state or prospects of industry or commerce, either generally or in any of their branches. The rate of interest, therefore, on good security, which alone we have here to consider (for interest in which considerations of risk bear a part may swell to any amount), is seldom, in the great centers of money transactions, precisely the same for two days together; as is shown by the never-ceasing variations in the quoted prices of the funds and other negotiable securities. Nevertheless, there must be, as in other cases of value, some rate which (in the language of Adam Smith and Ricardo) may be called the natural rate; some rate about which the market rate oscillates, and to which it always tends to