1. 1. In this way we here and in the following refer to Favaro'sEdizione Nazionale of Le Opere di Galileo Galilei(reprinted Firenze1929 ), indicating the volume with Roman, and the page with Arabic numerals.
2. 2. SeeKepler'sOpera Omnia, ed. Frisch, Vol. II,p. 232 , and Erlangen1859 .
3. 3. See Edward Rosen:Kepler's Conversation with Galileo's Sidereal Messenger, New York and London (Johnson)1965 , contains a great number of excellent notes and commentaries.
4. 4. Dioptrice Johannes Kepleri, reprinted in facsimile with an introduction by Michael Hoskin, Cambridge (Heffer)1962 .
5. 5. SeeRonchi:Histoire de la lumiere, traduit de l'Italien par Juliette Taton, Paris (Colin)1956 , pp. 65 seq.