Let us take on the other hand a different industry, one which utilises raw materials that form the substance of its product, and auxiliary materials that enter into the product bodily and not only as so much value, as is the case with fuel coal. The product, for instance the yarn, changes hands together with the raw material, the cotton, composing it, and passes from the process of production into that of consumption. But so long as the cotton functions as an element of productive capital, its master does not sell it, but processes it, has it made into yarn. He does not part with it. Or, to use Smith’s crudely erroneous and trivial terms, he does not make any profit “by parting with it, by its changing masters, or by circulating it.” He does not permit his materials to circulate any more than his machines. They are fixed in the process of production, the same as the spinning machines and the factory buildings. Indeed, a part of the productive capital must be just as continually fixed in the form of coal, cotton, etc., as in the form of instruments of labour. The difference is only that for instance the cotton, coal, etc., required for one week’s yarn production, are always entirely consumed in the manufacture of the weekly product, so that new cotton, coal, etc., must be supplied in their place; in other words, these elements of productive capital, although remaining identical in kind, always consist of new specimens of the same kind, while the same individual spinning machine or the same individual factory building continues its participation in a whole series of weekly productions without being replaced by a new specimen of its kind. As elements of the productive capital all its constituent parts are continually fixed in the process of production, for it cannot proceed without them. And all the elements of productive capital, whether fixed or circulating, equally confront, as productive capital, the capital of circulation, i.e., commodity-capital and money-capital.