Labour alone is the primary means of production; "the original purchase-money which has been paid for everything." Tools and materials, like other things, have originally cost nothing but labour; and have a value in the market only because wages have been paid for them. The labour employed in making the tools and materials being added to the labour afterwards employed in working up the materials by aid of the tools, the sum total gives the whole of the labour employed in the production of the completed commodity. In the ultimate analysis, therefore, labour appears to be the only essential of production. To replace capital, is to replace nothing but the wages of the labour employed. Consequently, the whole of the surplus, after replacing wages, is profits. From this it seems to follow, that the ratio between the wages of labour and the produce of that labour gives the rate of profit. And thus we arrive at Mr. Ricardo's principle, that profits depend upon wages; rising as wages fall, and falling as wages rise. To protect this proposition (the most perfect form in which the law of profits seems to have been yet exhibited) against misapprehension, one or two explanatory remarks are required. If by wages, be meant what constitutes the real affluence of the labourer, the _quantity_ of produce which he receives in exchange for his labour; the proposition that profits vary inversely as wages, will be obviously false. The rate of profit (as has been already observed and exemplified) does not depend upon the price of labour, but upon the proportion between the price of labour and the produce of it. If the produce of labour is large, the price of labour may also be large without any diminution of the rate of profit: and, in fact, the rate of profit is highest in those countries (as, for instance, North America) where the labourer is most largely remunerated. For the wages of labour, though so large, bear a less proportion to the abundant _produce_ of labour, there than elsewhere. But this does not affect the truth of Mr. Ricardo's principle as he himself understood it; because an increase of the labourer's real comforts was not considered by him as a rise of wages. In his language wages were only said to rise, when they rose not in mere quantity but in _value_. To the labourer himself (he would have said) the _quantity_ of his remuneration is the important circumstance: but its _value_ is the only thing of importance to the person who purchases his labour. The rate of profits depends not upon absolute or real wages, but upon the _value_ of wages.