Every labourer in adding new labour also adds new value. In what way? Evidently, only by labouring productively in a particular way: the spinner by his spinning, the weaver by his weaving, the smith by his forging. Each use-value disappears, only to reappear under a new form in some new use-value. By virtue of its general character, as being expenditure of human labour-power in the abstract, spinning adds a new value to the values of cotton and spindle. On the other hand, by virtue of its special character, as being a concrete, useful process, the same labour of spinning both transfers the values of the means of production to the product and preserves them in the product. Hence at one and the same time there is produced a twofold result. By the simple addition of a certain quantity of labour, new value is added, and by the quality of this added labour the original values of the means of production are preserved in the product. That part of capital which is represented by means of production, by the raw material, auxiliary material, and the instruments of labour, does not, in the process of production, undergo any quantitative alteration of value. I therefore call it the constant part of capital, or, more briefly, _constant capital_. On the other hand, that part of capital represented by labour-power does, in the process of production, undergo an alteration of value. It both reproduces the equivalent of its own value, and also produces an excess, a surplus value, which may itself vary. This part of capital is continually being transformed from a constant into a variable magnitude. I therefore call it the variable part of capital, or, shortly, _variable capital_. _IV.--Accumulation of Capital_ The first condition of the accumulation of capital is that the capitalist must have contrived to sell his commodities, and to re-convert the greater portion of the money thus received into capital. Whatever be the proportion of surplus-value which the industrial capitalist retains for himself or yields up to others, he is the one who, in the first instance, appropriates it. The process of production incessantly converts material wealth into capital, into means of creating more wealth and means of enjoyment for the capitalist. On the other hand, the labourer, on quitting the process, is nothing more than he was when he began it. He is a source of wealth, but has not the slightest means of making wealth his own. The product of the labourer is incessantly converted not only into commodities, but into capital, into means of subsistence that buy the labourer, and into means of production that command the producers. The capitalist as constantly produces labour-power; in short, he produces the labourer, but as a wage-labourer. This incessant reproduction, this perpetuation of the labourer, is the _sine qua non_ of capitalist production.