Like home circulation, international circulation requires a constantly changing quantity of gold and silver. A part of the accumulated hoards serves therefore, in each country as a reserve fund of world money, which now declines, now rises, according to the fluctuations of the exchange of commodities.[110] Besides the special movements which take place between national spheres of circulation, world-money possesses a universal movement, whose starting points are at the sources of production from which gold and silver streams spread out in different directions all over the world market. Here gold and silver enter the world circulation as commodities and are exchanged for commodity equivalents in proportion to the labor-time contained in them, before they penetrate national spheres of circulation. In the latter, they appear now with a given magnitude of value. Every fall or rise in the cost of their production equally affects, therefore, their relative value throughout the world market; on the other hand, that value is entirely independent of the extent to which the different national spheres of circulation absorb gold or silver. The part of the metal stream which is caught up by every separate sphere in the world of commodities, partly enters directly the home circulation of money to make up for worn out coin; partly is dammed up in the different reservoirs containing hoards of coin, means of payment and world-money; partly is turned into articles of luxury, while the rest simply forms a treasure. At an advanced stage of development of the capitalist system of production the formation of hoards is reduced to the minimum required by the various processes of circulation for the free play of their mechanism. The hoard as such becomes idle wealth, unless it appears as a temporary form of a surplus resulting from a favorable balance of payments or as the result of an interrupted exchange of matter, i. e. as the solidification of a commodity in its first metamorphosis.