The proof of this conduction is not far to seek: it is found in the common phenomenon of Dead Stock. However great the cost expended on an article, if the public will not have it, all the costs in Christendom will not give it a value; and, if the good continues “dead,” all the machinery and buildings by which it would have been made lose their value, except in as far as they can be turned to other uses, and get another value from another product. Even labour suffers. Whatever the expense of his special training, the labourer can give no value to his work, and loses his wage to the extent that he cannot adapt his skill to other employments. Suppose that an article of which there is a stock, goes out of fashion, the value and the price of it fall at once. The first thing the immediate manufacturer does is to ask himself if he can reduce his costs to suit the new price: if he cannot, he abandons the manufacture, and it passes probably to some man who is able to produce more cheaply, it may be by reducing wages and salaries, by new processes and more complicated machinery, or, perhaps, by employing women instead of men. In any case the cost must conform to the value. A striking proof of this is given in the case of silver. Most people have a dim idea that silver, as one of the precious metals, has a value almost innate. Yet after 1873 mine after mine was abandoned although the ores were as rich and the reefs as plentiful as ever. What was the cause?—Simply that silver was discarded as currency in certain countries: that is to say, silver fell in the estimation of great communities, and the loss of value was carried back till the price realised by the virgin silver was not enough to pay for the mining of it. Of course the identity of value between final product and groups of higher and higher rank is not absolute. It would be strange if it were; for where all the groups get their value from the last product, and this gets its value from a thing so inconstant as human want and so elastic as human provision, it is to be expected that the calculation which conducts value back and back, will, often enough, be mistaken. Builders tempted, by high freights at a time of sudden demand, to lay down a ship, must reckon with the possibility that, ere it be finished, the tide of prosperity may have ebbed, and that the price realised for the ship may scarce repay the wages and prices paid in anticipation. And, besides these fluctuations which cannot be reduced to law, and are often the chances on which the employer (as distinguished from the capitalist) makes his great profits—and losses—there is one constant difference between the value of the productive groups and that of the final product; that is, Interest. With this, however, we have no concern here. CHAPTER XIII FROM MARGINAL PRODUCTS TO COST OF PRODUCTION