1. Galileo’s Treatise de motu gravium,reprinted in Metaphysics and Measurement (London, 1968), p. 75.
2. Details are given in my `Hipparchus — Geminus — Galileo’, Stud. Hist. Philos. Science 20: 1 (1989), pp. 47–56.
3. Descartes to Marin Mersenne, 11 October 1638. Translated in S. Drake, Galileo at Work (Chicago 1978 ), pp. 387–8.
4. Benedetti’s proposition is translated in I. E. Drabkin & S. Drake, Mechanics in Sixteenth-Century Italy (Madison 1960), pp. 147–53 as it first appeared at Venice in 1553.
5. Translated in S. Drake, `A neglected Galilean letter’, Irnl. Hist. of Astron.
17 (1987), pp. 93–105.