which is not very appropriate, is derived from the circumstance, that this portion of capital requires to be constantly renewed by the sale of the finished product, and when renewed is perpetually parted with in buying materials and paying wages; so that it does its work, not by being kept, but by changing hands.
Another large portion of capital, however, consists in instruments of production, of a more or less permanent character; which produce their effect not by being parted with, but by being kept; and the efficacy of which is not exhausted by a single use. To this class belong buildings, machinery, and all or most things known by the name of implements or tools. The durability of some of these is considerable, and their function as productive instruments is prolonged through many repetitions of the productive operation. In this class must likewise be included capital sunk (as the expression is) in permanent improvements of land. So also the capital expended once for all, in the commencement of an undertaking, to prepare the way for subsequent operations: the expense of opening a mine, for example: of cutting canals, of making roads or docks. Other examples might be added, but these are sufficient. Capital which exists in any of these durable shapes, and the return to which is spread over a period of corresponding duration, is called Fixed Capital.
Of fixed capital, some kinds require to be occasionally or periodically renewed. Such are all implements and buildings: they require, at intervals, partial renewal by means of repairs, and are at last entirely worn out, and cannot be of any further service as buildings and implements, but fall back into the class of materials. In other cases, the capital does not, unless as a consequence of some unusual accident, require entire renewal: but there is always some outlay needed, either regularly or at least occasionally, to keep it up. A dock or a canal, once made, does not require, like a machine, to be made again, unless purposely destroyed, or
