_Practical distinctions._—The terms interest and rent are distinguished in actual practice by the fact that interest is paid for the use of capital in some circulating form, while rent is paid for the use of fixed capital. One who borrows anything, expecting to return not the thing itself but its equivalent in value, is said to borrow upon interest. One who borrows the same thing, expecting to return the identical thing, is said to pay rent for its use. Thus interest is paid for control of circulating capital until an equivalent is returned, and rent is paid for control of fixed capital until the same articles are returned in prime condition. A farmer who borrows a mowing machine from the warehouse, giving his note for its value, pays, when he returns that value at the end of the year, interest upon his note. If he borrows the same machine from his neighbor under contract to return the machine in good condition at the end of the season, he pays rent for its use. The young man who borrows his neighbor’s farm, expecting at the end of five years to make that farm his own, gives a mortgage note, promising at the end of five years to return an equivalent value for the farm, with annual interest. If, on the contrary, he expects to return the farm itself at the end of five years, without reduction in value, he makes a lease, embodying this agreement, with annual rent for use of the farm. Both interest and rent are liable to involve the element of risk as to the proper return of the valuable thing promised, and to that extent they partake of the nature of profits. The true interest and rent are independent of the possible risk, and have to do simply with the advantage naturally accruing to the possessor of wealth from its use as capital, and forming one of the chief reasons for accumulating wealth at all.