The fixed capital however requires also a positive expenditure of labour for its maintenance in good repair. The machinery must be cleaned from time to time. It is a question here of additional labour without which the machinery becomes useless, of merely warding off the noxious influences of the elements, which are inseparable from the process of production; hence it is a question of keeping the machinery literally in working order. It goes without saying that the normal durability of fixed capital is calculated on the supposition that all the conditions which it can perform its functions normally during that time are fulfilled, just as we assume, in placing a man’s life at 30 years on the average, that he will wash himself. It is here not a question of replacing the labour contained in the machine, but of constant additional labour made necessary by its use. It is not a question of labour performed by the machine, but of labour spent on it, of labour which it is not an agent of production but raw material. The capital expended for this labour must be classed as circulating capital, although it does not enter into the labour-process proper to which the product owes its existence. This labour must be continually expended in production, hence its value must be continually replaced by that of the product. The capital invested in it belongs in that part of circulating capital which has to cover the unproductive costs and is to be distributed over the produced values according to an annual average calculation. We have seen [Karl Marx, Capital, Vol. I, p. 426, Note 1. — Ed.] that in industry proper this labour of cleaning is performed by the workingmen gratis, during the rest periods, and for that very reason often also during the process of production itself, and most accidents can be traced to this source. This labour does not figure in the price of the product. As far as that goes the consumer receives it gratis. On the other hand the capitalist thus does not pay the maintenance costs of the machine. The labourer pays in persona, and this is one of the mysteries of the self-preservation of capital, which in point of fact constitute a legal claim by the labourer on the machinery, on the strength of which he is a co-owner of the machine even from the standpoint of bourgeois law. However, in various branches of production, in which the machinery must be removed from the process of production for the purpose of cleaning and where therefore the cleaning cannot be performed in between, as for instance in the case of locomotives, this maintenance work counts as current expenses and is therefore an element of circulating capital. For instance a goods engine should not run more than 3 days without being kept one day in the shed. If you attempt to wash out the boiler before it has cooled down that is very injurious. (R.C., No. 17823.)