Not all this variety is essential to an efficient monetary system and several of the kinds survive as the result of historical accidents (political and legislative). But all are now kept in accord with the value of the gold coin which, it will be observed, is the only kind the amount of which is not artificially limited. Silver dollars are no longer coined, subsidiary silver and minor coins are issued only in exchange for other money, as are gold and silver certificates in exchange for gold or for silver, which they merely represent while in circulation. § 3. #Saturation point of fractional money.# Fiduciary money is that on which regularly the issuer makes a seigniorage charge.[3] Let us consider now the effect of seigniorage on the value of money. Fractional coins are those of smaller denominations than the standard unit of money, as shillings and pence in England, and half dollars, quarter dollars, dimes, nickels, and cents in America. Money to serve well a variety of uses must be of different denominations, and "small change" is necessary to make small purchases and for exact settlement in larger payments that are not multiples of the standard unit. The amount required (or most convenient to use) in each denomination of fractional coins is thus a more or less certain portion of each person's monetary demand, shaped by experience and fixed by habit. For example, within certain elastic limits of convenience quarters may be used for halves, and dimes for nickels (and _vice versa_); but each person has a point of preference. The total demand for each kind of change is the sum of the individual demands. This point where the amount of coins of any denomination (in relation to the whole monetary system) is most convenient may be called the saturation point of that kind of small change, up to which point the people prefer a share of their money in that form, and beyond which they will, if free to choose, exchange that kind for other denominations (smaller or larger). Each kind of money, as the cent, nickel, dime, has its own peculiar demand and its saturation point. MONETARY SYSTEM OF THE UNITED STATES, 1915