3. The value-part of the productive capital, the part invested in fixed capital, is advanced in one lump sum for the entire period of employment of that part of the means of production of which the fixed capital consists. Hence this value is thrown into the circulation by the capitalist all at one time. But it is withdrawn again from the circulation only piecemeal and gradually by realising the parts of value which the fixed capital adds piecemeal to the commodities. On the other hand the means of production themselves, in which a component part of the productive capital becomes fixed, are withdrawn from the circulation all at one time to be embodied in the process of production for the entire period in which they function.
But they do not require for this period any replacement by new samples of the same kind, do not require reproduction. They continue for a longer or shorter period to contribute to the creation of the commodities thrown into circulation without with-drawing from circulation the elements of their own renewal. Hence they do not require from the capitalist a renewal of his advance during this period. Finally the capital-value invested in fixed capital does not pass bodily through the circuit of its forms, during the functioning period of the means of production in which this capital-value exists, but only as concerns its value, and even this it does only parts and gradually. In other words, a portion of its value is continually circulated and converted into money as a part of the value of the commodities, without being reconverted from money into its original bodily form. This reconversion of money into the bodily form of the means of production does not take place until the end of its functioning period, when the means of production has been completely consumed.
4. The elements of circulating capital are as permanently fixed in the process of production -- if it is to be uninterrupted -- as the elements of fixed capital. But the elements of circulating capital thus fixed are continually renewed in kind (the means of production by new products of the same kind, labour-power by constantly renewed purchases) while in the case of the elements of fixed capital neither they themselves are renewed nor need their purchases be renewed so long as they continue to exist.
There are always raw and auxiliary materials in the process of production, but always new products of the same kind, after the old elements have been consumed in the creation of the finished product. Labour-power likewise always exists in the process of production, but only by means of ever new purchases, frequently involving changes of persons. But the same identical buildings, machines, etc., continue to function, during repeated turnovers of the circulating capital, in the same repeated processes of production.
II. COMPONENTS, REPLACEMENT, REPAIR, AND ACCUMULATION OF FIXEDCAPITALIn any investment of capital the separate elements of the fixed capital have different lifetimes, and therefore different turnover times. In a railway, for instance, the rails, sleepers, earthworks, terminals, bridges, tunnels, locomotives, and carriages have different functional periods and times of reproduction, hence the capital advanced for them has different times of turnover. For a great number of years, buildings, platforms, water tanks, viaducts, tunnels, cuttings, dams, in short everything called "works of art" in English railroading, do not require any renewal. The things which wear out most are the tracks and rolling stock.
Originally in the construction of modern railways it was the prevailing opinion, nursed by the most prominent practical engineers, that a railway would last a century and that the wear and tear of the rails was so imperceptible that it could be ignored for all financial and other practical purposes;100 to 150 years was supposed to be the life of good rails. But it was soon found that the life of a rail, which naturally depends on the speed of the locomotives, the weight and number of trains, the diameter of the rails, and on a multitude of other attendant circumstances, did not exceed an average of 20 years. In some railway terminals, great traffic centres, the rails even wear out every year. About 1867 began the introduction of steel rails, which cost about twice as much as iron rails but which last more than twice as long. The life-time of wooden sleepers was from 12 to 15 years. It was also ascertained with regard to the rolling stock that freight cars wear out faster than passenger cars. The life of a locomotive was estimated in 1867 to be about 10 to 12 years.
The wear and tear is first of all a result of use. As a rule "the wear of the rails is proportionate to the number of trains." (R.C., No.
17645.) [22] With increased speed the wear and tear of a railway increased in a higher ratio than the square of the speed; that is to say, if you doubled the speed of the engine, you more than quadrupled the cost of wear and tear of the road. (R.C., No. 17046.)Wear and tear is furthermore caused by the action of natural forces.
For instance sleepers suffer not only from actual wear but also from rot.
"The cost of maintaining the road does not depend so much upon the wear and tear of the traffic passing over it, as upon the quality of wood, iron, bricks and mortars exposed to the atmosphere. A month of severe water would do not more damage to the road of a railway than a year's traffic." (R.
