Lastly, take the case of Labour. Here we have a productive good of the same nature as iron in that it is capable of employment in an infinite number of ways. The labouring power of a nation, like all its other productive goods, goes steadily into the most remunerative employments one after another. But, of all productive goods, labour shows most evidently that it has no predetermined value, but gets its value entirely from what it produces. Consequently, the price of labour is, naturally, as variable as the price of its products. Some products of labour will for the time fetch a price equal to 10/ a day of wage; others, prices equal to 9/; and so on down the scale, perhaps, to 3/ per day. If the available labour as a whole is taken up at that wage, those products of labour which pay 3/ per day of price to labour will assert themselves as the marginal products, and that wage will seem in its turn to determine the value of other products. But if population goes on increasing, other things remaining the same, and a new supply of labour comes forward, this labour will inevitably seek lower levels of demand—for, of all goods, labour is the one that will not “keep.” On the other hand, there are at any time endless wants waiting on satisfaction, but not able to pay the marginal cost of satisfaction, the 3/ per day. Consequently, as buyers with a lower valuation than the marginal one, they do not affect price. But now the new surplus supply of labour and the unsatisfied layer of wants come together. Labour is set to satisfy wants that offer, say, 2/6 per day of wage for their satisfaction, and the products thus resulting become the marginal products. Happily for the labourer, competition cannot do its perfect work where the commodity bought and sold is human life: but, if labour were entirely mobile, it would only be a question of time till the marginal product fixed the wage of labour generally, and wages fell in harmony with the new marginal costs—the low wage for what the labourers produced being, let us hope, more than recouped by the universal fall in prices of what the labourers consumed. CHAPTER XV CONCLUSION Thus we have found that what determines the value of productive goods where the product is one single good directly connected with them, and what determines it in the most complicated cases, where the conduction of value is, first, to means of production, and, then, back again to product, is always the marginal utility, the utility of the marginal product. As the vineyards of Tokay get their value from the wine of their grapes, and as cotton gets its value from the bare backs it covers, so do iron, coal, and labour get their value in the last resort—far as may be the course from post to finish—from the last employment into which they enter.