1. [Marshall pointed out that the assumption of a constant purchasing power of money is a convenience which permits the relation of the price of anything to the mean or average purchasing power and is likened to the assumptions made by astronomers to a ‘“mean sun” which crosses the meridian at uniform intervals so that the clock can keep pace with it; whereas the actual sun crosses the meridian sometimes before and sometimes after noon as shown by the clock’ A. Marshall, Principles, of Economics: An Introductory Volume, 8th edn (London: Macmillan, 1920), p. 62, n.1.
2. See Alfred Marshall, Principles of Economics, 9th (variorum) edn by C. W. Guilleband, II Notes (London: Macmillan for the Royal Economic Society, 1961), p. 191.]
3. See, for example, F. A. von Hayek, Prices and Production (London: Routledge, 1931)
4. and Vera Clarke Smith, The Rationale of Central Banking (London: P. S. King, 1936)
5. Keynes referred to Cassel’s On the Nature and Necessity of Interest (Stockholm, 1903, repr. New York: Kelley & Millman, 1957).