1. Cf. M. B. Hesse,Models and Analoges in Science, London, 1963, pp. 68 and 77.
2. Isaac Newton,Opticks.Reprinted: Dover Books, New York, 1952, p. 402.
3. Plato,Timaeus.Everyman's Library, London, 1965, 30D–31A.
4. Cf. M. Rouché,La philosophie de l'histoire de Herder, Paris, 1940, pp. 215–16.