* For Engels’s explicit analogy between Marx’s theory of value and the refutation of the phlogiston theory, see his Preface to Volume 2 of Capital, pp. 97–8.

† Marx criticized the theoretical basis of Proudhon’s ‘People’s Bank’ in The Poverty of Philosophy (1847). In January 1849, Proudhon established his bank in Paris, and in line with his doctrine its practice included the extension of interest-free credit (crédit gratuit). After two months the bank went into forced liquidation. See also below, p. 743. From the 1840s through to his death in 1864, Pierre-Joseph Proudhon, a worker in origin, was the most influential French socialist theorist, and as such the object of frequent criticism by Marx. Cf. Grundrisse, pp. 137, 248, 264–6, 424–6, 488, 640–41, 754–8, and 843–5.