[4] What is commonly termed land contains elements which perish in the using. Such are deposits of coal, ores, or oil, and those ingredients of loam which are exhausted by tillage. Such elements of the soil are not land in the economic sense. How they should be regarded will be shown in a later chapter. _Mobility an Attribute of Capital._--Even in a static society capital would be permanent, while particular capital goods would be perishable. In dynamic studies another quality of capital, as distinguished from capital goods, comes into the foreground, namely, mobility. It is the power to move without loss from one industry to another. Goods cannot be thus moved with any freedom. A loom cannot be taken out of a woolen mill and made to do duty in a carpenter's shop, nor can a circular saw be made available in weaving. When the loom wears out and needs replacement, it is in the owner's power to procure either another loom or a circular saw, and if he chooses the latter alternative, he causes capital to move into the woodworking business. A whaling ship would not be useful as a cotton mill; but much capital that was once invested in the whale fishery of New England has since found its way into manufacturing. The transfer can often be made without waste. If the earnings of an instrument have sufficed to replace it with another that is like it, they may suffice for producing an instrument that is unlike it. Waste, if it occurs, results from a failure of the original instrument to earn the fund for replacement. Capital which thus abides but passes from one employment to another is a body the identity and the character of whose component parts change. The transfer of capital from one industry to another is a dynamic phenomenon which is later to be considered. What is here important is the fact that it is in the main accomplished without entailing transfers of capital goods. An instrument wears itself out in one industry, and instead of being succeeded by a like instrument in the same industry, it is succeeded by one of a different kind which is used in a different branch of production. Goods have not moved from one branch to another, but capital has done so. _How Capital itself may be Destroyed._--When we speak of capital as permanent, we mean that using does not destroy it as it destroys the tissues of which it is composed. Fires, earthquakes, and business disasters put parts of it out of existence and affect the volume of the fund as a whole; but production itself leaves it intact. It is this very production which destroys capital goods and makes it necessary to replace them. CHAPTER III THE MEASURE OF CONSUMERS' WEALTH