◆¹ And next, with more brevity, let us consider the manufacture of iron. By and by we shall come back to the subject; so it will be enough here to mention a single fact connected with it. From about the year 1740, when a careful and comprehensive inquiry into the matter was made, up to the year 1780, the average produce of each smelting furnace in the country was _two hundred and ninety-four tons_ of iron annually. Towards the close of this period machinery had been invented by which a blast was produced of a strength that had been unknown previously; and in the year 1788, the average product of each of these same furnaces was _five hundred and ninety-five tons_, or very nearly double what it had been previously. An extra _two hundred and fifty tons_ was produced from each furnace annually: and if we attribute the whole of the former product to human exertion, _two hundred and fifty tons_ at all events was the product of the new machinery; since if that had been destroyed, the product, in proportion to the expenditure of exertion, would at once have sunk back to what it had been forty-eight years earlier. [Sidenote ◆1 The products, then, of Capital embodied in machinery are easily distinguishable from the products of Labour.] ◆¹ Here, then, we have before us the two principal manufactures of this country, as they were during the closing years of the last century; and we have seen that in each a definite portion of the product was due to a certain kind of capital, as distinct from human exertion—distinct from human exertion in precisely the same way, as we have already seen land to be, when we find it producing rent; and we have seen further that the products both of this kind of Capital and of Land, are to be distinguished from those of Human Exertion on precisely similar principles.[30] [Sidenote ◆1 In the next chapter we will consider the products of Wage Capital.] ◆¹ Machinery, however,—or fixed capital, of which we have taken machinery as the type,—is only a part of Capital considered as a whole. We have still to deal with the part that is reserved for and spent in wages; and this will introduce us to an entirely new subject—a subject which as yet I have not so much as hinted at—namely human exertion considered in an entirely new light. CHAPTER IV _Of the Products of Circulating Capital, or Wage Capital, as distinguished from the Products of Human Exertion._ [Sidenote ◆1 Wage Capital enables men to undertake work which will not support them till a considerable time has elapsed.]