In the international circulation of commodities, gold and silver appear not as mediums of circulation, but as universal mediums of exchange. The universal medium of exchange performs its function only under its two developed forms of a means of purchase and of a means of payment, whose mutual relation in the world market is the very reverse of what it is at home. In the sphere of home circulation, money in the form of coin, played exclusively the part of a means of purchase, either as the intermediary in the dynamic unity C―M―C or as the representative of the transient form of exchange value in the unceasing change of positions by commodities. In the world market it is just the contrary. Gold and silver appear here as a means of purchase when the exchange of matter is but one-sided, and purchase and sale do not coincide. The frontier trade at Kiachta e. g. is both actually and according to treaty, one of barter, in which silver plays only the part of a measure of value. The war of 1857-58 compelled the Chinese to sell without buying. Silver suddenly appeared now as a means of purchase. Out of regard to the letter of the treaty, the Russians made up the French five frank coins into crude silver commodities, which were made to serve as a means of exchange. Silver has always served as a means of purchase between Europe and America on one side and Asia on the other, where it settles down in the form of hoards. Furthermore, the precious metals serve as international means of purchase whenever the ordinary balance of exchange of matter between two nations is suddenly upset, as e. g. when a failure of crops forces one of them to buy on an extraordinary scale. Finally, the precious metals are international means of purchase in the hands of gold and silver producing countries, in which case they directly constitute a product and commodity and not merely a converted form of a commodity. The more the exchange of commodities between different national spheres of circulation is developed, the more important becomes the function of world money to serve as a _means of payment_ for the settlement of international balances.