In the case of an altogether declining trade, in which it is necessary that the production should be, not occasionally varied, but greatly and permanently diminished, or perhaps stopped altogether, the process of extricating the capital is, no doubt, tardy and difficult, and almost always attended with considerable loss; much of the capital fixed in machinery, buildings, permanent works, etc., being either not applicable to any other purpose, or only applicable after expensive alterations; and time being seldom given for effecting the change in the mode in which it would be effected with least loss, namely, by not replacing the fixed capital as it wears out. There is besides, in totally changing the destination of a capital, so great a sacrifice of established connection, and of acquired skill and experience, that people are always very slow in resolving upon it, and hardly ever do so until long after a change of fortune has become hopeless. In general, then, although profits are very different to different individuals, and to the same individual in different years, there can not be much diversity at the same time and place in the average profits of different employments (other than the standing differences necessary to compensate for difference of attractiveness), except for short periods, or when some great permanent revulsion has overtaken a particular trade. It is true that, to persons with the same amount of original means, there is more chance of making a large fortune in some employments than in others. But it would be found that in those same employments bankruptcies also are more frequent, and that the chance of greater success is balanced by a greater probability of complete failure. § 4. The Cause of the Existence of any Profit; the Advances of Capitalists consist of Wages of Labor. The preceding remarks have, I hope, sufficiently elucidated what is meant by the common phrase, “the ordinary rate of profit,” and the sense in which, and the limitations under which, this ordinary rate has a real existence. It now remains to consider what causes determine its amount.