1. See articles on Leonardo in Dictionary of Scientific Biography， ed. Charles Coulston Gillespie （Scribner， New York， 1970）， Volume 8， pp. 192–245.
2. Quotations are from René Descartes， Principles of Philosophy， trans. V. R. Miller and R. P. Miller （D. Reidel， Dordrecht， 1983）， p. 15.
3. Voltaire， Philosophical Letters， trans. E. Dilworth （Bobbs-Merrill Educational Publishing， Indianapolis， Ind.， 1961）， p. 64.
4. It is odd that many modern English language editions of Discourse on Method leave out these supplements， as if they would not be of interest to philosophers. For an edition that does include them， see René Descartes， Discourse on Method， Optics， Geometry， and Meteorology， trans. Paul J. Olscamp （Bobbs-Merrill， Indianapolis， Ind.， 1965）。 The Descartes quote and the numerical results below are from this edition.
5. It is argued that the tennis ball analogy fits well with Descartes’ theory of light as arising from the dynamics of the tiny corpuscles that fill space; see John A. Schuster， “Descartes Opticien—The Construction of the Law of Refraction and the Manufacture of Its Physical Rationales， 1618–29，” in Descartes’ Natural Philosophy， ed. S. Graukroger， J. Schuster， and J. Sutton （Routledge， London and New York， 2000）， pp. 258–312.
6. Aristotle， Meteorology， Book III， Chapter 4， 374a， 30–31 （Oxford trans.， p. 603）。
7. Descartes， Principles of Philosophy， trans. V. R. Miller and R. P. Miller， pp. 60， 114.
8. On this point， see Peter Dear， Revolutionizing the Sciences— European Knowledge and Its Ambitions， 1500–1700， 2nd ed. （Princeton University Press， Princeton， N.J.， and Oxford， 2009）， Chapter 8.
9. L. Laudan， “The Clock Metaphor and Probabilism： The Impact of Descartes on English Methodological Thought，” Annals of Science 22， 73 （1966）。 Contrary conclusions were reached in G. A. J.Rogers， “Descartes and the Method of English Science，” Annals of Science 29， 237 （1972）。
10. Richard Watson， Cogito Ergo Sum—The Life of René Descartes （David R. Godine， Boston， Mass.， 2002）。
