_Elements of Cost._--Whatever the _entrepreneur_ has to pay for in the production of an article is of course an element in its monetary cost to him. If he does not begin the making of it by drawing his raw materials from what nature freely furnishes, he must pay some one for the raw material. He must also pay for the labor, and this is equivalent to buying the fraction of the article that is produced by labor; for the laborer, as we have seen, is the producer of a certain fractional share of the article and the natural owner of that share, and when he agrees to let his labor for hire, what he really does is to sell out his individual interest in the forthcoming product of the industry in which he is about to engage. When a workman in a shoe factory agrees to work for two dollars and a half a day, he really contracts to sell every day for that amount a certain quantity of shoes. The leather is one element which enters into the finished shoes, and therefore the entire shoe is not really made in the factory; but of the part which is there made, namely, the utility that results from transforming the leather into shoes, one part is made by labor and another by capital. The _entrepreneur_ has to buy both of these if he is to acquire a valid title to the product and have a right to sell it. These costs are therefore "purchase money" paid for undivided shares of goods. _Labor of Management._--It usually happens that an _entrepreneur_, or employer of labor and capital, performs some labor himself; and we have already noted the reason for this in the fact that the kind of labor that he performs is so important that the fate of the business often depends on it. He may manage the business so well as to make it succeed or so ill as to make it fail. He pays himself for this labor when he draws a salary for his services. As an _entrepreneur_ he treats his own labor as he does that of any one else and buys the fraction of the product of his business that his own labor of management has created. In this he illustrates the general law that all payments of wages are payments of the purchase of a certain quantity of product. Though the owner's own contribution to the product is not always mentioned in terms in the accounting, that is what his salary is paid for, though it is spoken of as a payment for his "time," or his labor.