means of exchange. I cannot therefore express this certain amount of labor-time in labor hours, since their number is not known to me, but I can express it relatively in terms of another commodity, which has the same amount of labor time incorporated in it. The clock is worth as much as the piece of cloth.
But while the production of commodities and the exchange of commodities compel the society resting upon them to take this roundabout course, they are impelled to a shortening of the process. They separate from the mass of commodities one sovereign commodity, in which the value of all other commodities can be universally expressed, a commodity which is the complete incarnation of social labor, and, against which, all other commodities may be set in direct comparison gold. Gold already germinates in the idea of value, it is only developed value. But since the commodity value exists in gold also, itself being a commodity, a new factor arises in the society which produces and exchanges commodities, a factor with new social functions and operations. We can now examine this a little more closely.
The economy of the production of commodities is by no means the only science which has to reckon with relatively known factors. Even in physics, we do not know how many single gas molecules there are in a given volume of gas, pressure and temperature being given. But we know, as far as Boyle s law is correct, that a given volume of that gas has as many molecules as a similar volume of another selected gas at the same pressure and the same temperature. We can therefore compare the different volumes of different gases with respect to their molecular content, and, if we take one litre of gas at O Fahrenheit as the unit we can refer the molecular content of each to this standard. In
