"The object at which we aim is, as it seems to me, a currency which shall keep prices stable, a currency which shall expand, therefore, with the expansion of trade and commerce and development generally, a currency which shall not be lagging behind the commerce and development of the country, and hindering that development, and a currency which shall not, by being too rapidly increased, lead to excessive speculation and to loss." We may summarize these conclusions in regard to money then as follows:-- Money should have an invariable value. The test of invariable money value is stability of prices in general. The value of money depends on the supply of it relative to the demand for it. The demand for money is variable and uncertain. It is affected by a great variety of circumstances, most of which are beyond control. The supply is in all cases regulated directly or indirectly by law, and can be controlled. In any monetary system it is necessary, therefore, that the supply should adjust itself quickly and correctly to any changes in demand, so that prices of all commodities shall, on the average, neither rise nor fall. In this way, and in no other, can an honest money be obtained. It is believed that these conclusions cannot be successfully controverted, and, using them as a basis, we now purpose to examine existing monetary systems, and some proposed changes therein, to see in how far they conform to this requirement, and what can be done for their improvement. CHAPTER III. EXISTING MONETARY SYSTEMS. Various substances have been used as money in the past. The "survival of the fittest" has, however, eliminated all but three (omitting fractional coins), and these are used, singly or in combination, at present in all the civilized nations of the world. These three are gold, silver, and paper. Gold and silver are generally used in the form of coins of definite weight and fineness. Paper money is a promissory note issued by the government, or by authorized banks, promising to pay the bearer, on demand, the amount of coin specified on its face. Where this promise is kept, and coin is paid on demand, the paper is said to be convertible. Where, for any reason, the promise is not kept, and the amount of coin specified will not be given on demand, the paper is called inconvertible or irredeemable. As the coins which are used, and which are promised to be given in exchange for paper, may be either of gold or silver, or both, the system is said to be a gold standard or a silver standard, according to which one is used, or a bi-metallic standard if both are used under certain conditions. At present, as will be explained in considering that system, there is no country that is really using a bi-metallic standard.