While prices remain constant, She quantity of the circulating medium may increase owing to the number of circulating commodities increasing, or to the velocity of currency decreasing, or to a combination of the two. On the other hand the quantity of the circulating medium may decrease with a decreasing number of commodities, or with an increasing rapidity of their circulation.
With a general rise in the prices of commodities, the quantity of the circulating medium will remain constant, provided the number of commodities in circulation decrease proportionally to the increase in their prices, or provided the velocity of currency increase at the same rate as prices rise, the number of commodities in circulation remaining constant. The quantity of the circulating medium may decrease, owing to the number of commodities decreasing more rapidly; or to the velocity of currency increasing more rapidly, than price rise.
With a general fall in the prices of commodities, the quantity of the circulating medium will remain constant, provided the number of commodities increase proportionally to their fall in price, or provided the velocity of currency decrease in the same proportion. The quantity of the circulating medium will increase, provided the number of commodities increase quicker, or the rapidity of circulation decrease quicker, than the prices fall.
The variations of the different factors may mutually compensate each other, so that notwithstanding their continued instability, the sum of the prices to be realised and the quantity of money in circulation remain constant; consequently, we find, especially if we take long periods into consideration, that the deviations from the average level, of the quantity of money current in any country, are much smaller than we should at first sight expect, apart of course from excessive perturbations periodically arising from industrial and commercial crises, or, less frequently, from fluctuations in the value of money.
The law, that the quantity of the circulating medium is determined by the sum of the prices of the commodities circulating, and the average increasing more rapidly, than prices velocity of currency may also be stated as follows: given the sum of the values of commodities, and the average rapidity of their metamorphoses, the quantity of precious metal current as money depends on the value of that precious metal. The erroneous opinion that it is, on the contrary, prices that are determined by the quantity of the circulating medium, and that the latter depends on the quantity of the precious metals in a country; this opinion was based by those who first held it, on the absurd hypothesis that commodities are without a price, and money without a value, when they first enter into circulation, and that, once in the circulation, an aliquot part of the medley of commodities is exchanged for an aliquot part of the heap of precious metals.
C. Coin and symbols of value
That money takes the shape of coin, springs from its function as the circulating medium. The weight of gold represented in imagination by the prices or money-names of commodities, must confront those commodities, within the circulation, in the shape of coins or pieces of gold of a given denomination. Coining, like the establishment of a standard of prices, is the business of the State. The different national uniforms worn at home by gold and silver as coins, and doffed again in the market of the world, indicate the separation between the internal or national spheres of the circulation of commodities, and their universal sphere.
The only difference, therefore, between coin and bullion, is one of shape, and gold can at any time pass from one form to the other. But no sooner does coin leave the mint, than it immediately finds itself on the high-road to the melting pot. During their currency, coins wear away, some more, others less. Name and substance, nominal weight and real weight, begin their process of separation. Coins of the same denomination become different in value, because they are different in weight. The weight of gold fixed upon as the standard of prices, deviates from the weight that serves as the circulating medium, and the latter thereby ceases any longer to be a real equivalent of the commodities whose prices it realises. The history of coinage during the middle ages and down into the 18th century, records the ever renewed confusion arising from this cause. The natural tendency of circulation to convert coins into a mere semblance of what they profess to be, into a symbol of the weight of metal they are officially supposed to contain, is recognised by modern legislation, which fixes the loss of weight sufficient to demonetise a gold coin, or to make it no longer legal tender.