The commodity that I have sold to you differs from the crowd of
 other commodities, in that its use creates value, and a value greater than
 its own. That is why you bought it. That which on your side appears a spontaneous
 expansion of capital, is on mine extra expenditure of labour-power. You
 and I know on the market only one law, that of the exchange of commodities.
 And the consumption of the commodity belongs not to the seller who parts
 with it, but to the buyer, who acquires it. To you, therefore, belongs
 the use of my daily labour-power. But by means of the price that you pay
 for it each day, I must be able to reproduce it daily, and to sell it again.
 Apart from natural exhaustion through age, &c., I must be able on the
 morrow to work with the same normal amount of force, health and freshness
 as to-day. You preach to me constantly the gospel of “saving” and “abstinence.”
 Good! I will, like a sensible saving owner, husband my sole wealth, labour-power,
 and abstain from all foolish waste of it. I will each day spend, set in
 motion, put into action only as much of it as is compatible with p225its
 normal duration, and healthy development. By an unlimited extension of
 the working-day, you may in one day use up a quantity of labour-power greater
 than I can restore in three. What you gain in labour I lose in substance.
 The use of my labour-power and the spoliation of it are quite different
 things. If the average time that (doing a reasonable amount of work) an
 average labourer can live, is 30 years, the value of my labour-power, which
 you pay me from day to day is 1/(365×30) or 1/10950 of its total value.
 But if you consume it in 10 years, you pay me daily 1/10950 instead of
 1/3650 of its total value, i.e., only 1/3 of its daily value,
 and you rob me, therefore, every day of 2/3 of the value of my commodity.
 You pay me for one day’s labour-power, whilst you use that of 3 days. That
 is against our contract and the law of exchanges. I demand, therefore,
 a working-day of normal length, and I demand it without any appeal to your
 heart, for in money matters sentiment is out of place. You may be a model
 citizen, perhaps a member of the Society for the Prevention of Cruelty
 to Animals, and in the odour of sanctity to boot; but the thing that you
 represent face to face with me has no heart in its breast. That which seems
 to throb there is my own heart-beating. I demand the normal working-day
 because I, like every other seller, demand the value of my commodity. [6]