Galileo, the Telescope, and the Science of Optics in the Sixteenth Century A Case Study of Instrumental Practice in Art and Science Sven Dupré Proefschrift voorgelegd ter behaling van de graad van doctor in de wijsbegeerte Promotor : Prof. dr. Marc De Mey | Co-Promotor : Prof. dr. Fernand Hallyn Universiteit Gent - 2002 Contents List of illustrations page IV Acknowledgements XI Chapter I. Galileo’s Telescope in the History of Science 1 Chapter II. The Appropriation of Optics in the Sixteenth Century: Sixteenth Century Mathematical Practitioners and Medieval Optics 17 Chapter III. Optics and Instrument Design in the Sixteenth Century: Breaking Rays and Shadows Running Backwards 84 Chapter IV. The Point of Inversion in Sixteenth Century Optics: The ‘Theory of the Concave Spherical Mirror’ of Ettore Ausonio 127 Chapter V. Galileo, Mathematical Practitioner: His Early Sources on Optics 175 Chapter VI. ‘As Distant Cities in Flemish Paintings’: The Point of Inversion and the Invention of the Telescope 234 Chapter VII. ‘As Little Moons’: Galileo’s Exploration of Light 285 Chapter VIII. Postscript: Big History, Small History 319 Appendix I. Ausonio, Fragments 323 Appendix II. Transcription and Translation: Ausonio’s ‘Theorica Speculi Concavi Sphaerici’ 326 Abstract 327 Bibliography 333 III List of Illustrations List of Illustrations Cover Illustration Hans Bol, Flood Lanscape with a View of a City, 1562, ADV (Graz). Chapter I. Galileo’s Telescope in the History of Science. 1. Galileo, Telescope I, Museo di Storia della Scienza (Florence). 2. Replica of Telescope I by the Author. 3. Galileo, Telescope II, Museo di Storia della Scienza (Florence). 4. Galileo, Single Broken Lens, Museo di Storia della Scienza (Florence). 5. Design of a Galilean Telescope: Focal Distances and Length. 6. Cardboard Ring of Telescope I, Museo di Storia della Scienza (Florence). 7. Cardboard Ring of Telescope II, Museo di Storia della Scienza (Florence). Chapter II. The Appropriation of Optics in the Sixteenth Century: Sixteenth Century Mathematical Practitioners and Medieval Optics. 1. Multiplication of Species, from Cesare Cesariano, Vitruvio … de Architectura Libri Dece[m] traducti de latino in Vulgare affigurati, Commentati …, 1521, f. 11v. 2. Measuring the Height of a Tower, from Leon Battista Alberti, Ludi Rerum Mathematicarum, In Opere Volgari, edited by Cecil Grayson, p. 136. 3. Fontana, Magic Lantern, from Giovanni Fontana, Bellicorum Instrumentorum Liber, Bayerische Staatsbibliothek (München), Cod. Icon. 242, f. 70. 4. Mirror Anamorphosis, from Jean-François Niceron, La Perspective Curieuse, 1652. 5. Optical Trick, from Egnazio Danti, Le Due Regole della Prospettiva Practica, 1583, p. 95. 6. Instrument of Laureti to View Anamorphosis, from Egnazio Danti, Le Due Regole della Prospettiva Practica, 1583, p. 96. 7. Anamorphosis, from Lodovico Cigoli, Trattato Pratico di Prospettiva di Ludovico Cardi detto il Cigoli, Gabinetto dei Disegni e Delle Stampe degli Uffizi (Florence), 2660a, f. 92v. 8. Instrument for Anamorphosis, from Jean-François Niceron, La Perspective Curieuse, 1652. 9. Frontispiece of Witelo’s Perspectiva, from Vitellonis Mathematici doctissimi peri optikes, … nunc primam opera … Georgii Tanstetter et Petri Apiani in lucem aedit, 1535. 10. Frontispiece of Witelo’s Perspectiva, from Fredericus Risner Opticae Thesaurus, 1572. 11. Construction of a Parabola, from Jean Fusoris, Liber Seccione Mukesi, in Clagett, Marshall. Archimedes in the Middle Ages. Vol. 4: A supplement on the medieval Latin traditions of conic sections. Philadelphia: The American Philosophical Society, 1980. 12. Compass to Draw a Parabola, from Jean Fusoris, Liber Seccione Mukesi, in Clagett, Marshall. Archimedes in the Middle Ages. Vol. 4: A supplement on the medieval Latin traditions of conic sections. Philadelphia: The American Philosophical Society, 1980. 13. Measuring the Height of a Tower, from Giovanni Fontana, Bellicorum Instrumentorum Liber, Bayerische Staatsbibliothek (München), Cod. Icon. 242, f. 49. IV List of Illustrations 14. Mirrors, from Giovanni Fontana, Giovanni Fontana, Bellicorum Instrumentorum Liber, Bayerische Staatsbibliothek (München), Cod. Icon. 242, f. 42. 15. Construction of a Parabola, from Oronce Fine, Opere di Orontio Fineo del Delfinato Divise in Cinque Parti, Arimetica, Geometria, Cosmografia, e Orivoli, 1587, f. 14. 16. Construction of a Parabola, from John Baptista Porta, Natural Magick, 1658, p. 372. 17. Parabolic Compass, from Jacomo Contarini, Figure d’ Istromenti e Loro Uso, Bodleian Library (Oxford), Canon. Ital. 145, f. 13. 18. Classification of the Mathematical Arts, from John Dee, The Mathematicall Praeface to the Elements of Geometrie of Euclid of Megara, 1570, John Dee, Groundplat. 19. Image Formation in a Convex Mirror, from John Dee, De Speculis Comburentibus Libri 5, Bodleian Library (Oxford), Cotton Vitellius C. VIII, f. 305v. 20. Instrument to Measure Angles of Reflection, from John Dee, De Speculis Comburentibus Libri 5, Bodleian Library (Oxford), Cotton Vitellius C. VIII, f. 308v. Chapter III. Optics and Instrument Design in the Sixteenth Century: Breaking Rays and Shadows Running Backwards. 1. Celestial Vault: Zenith, Nadir, Horizon, North and South Celestial Pole, Prime Meridian. 2. Celestial Vault: Equinoctial, Tropics, Equinoxes, Solstices, Ecliptic. 3. Construction of a Refractive Scaphe Dial. 4. Ptolemy’s Instrument to Measure Refraction. 5. Tabulations of Refraction, from Witelo, Opticae Thesaurus, 1572, p. 412. 6. Refractive Scaphe Dial, from Mutio Oddi, De gli Horologi Solari Trattato, 1638, p. 101. 7. Refractive Scaphe Dial of Georg Hartmann, 1547, Museo de Santa Cruz (Toledo). 8. Refractive Scaphe Dial of Georg Hartmann, 1547, Sold at Sotheby’s. 9. Refractive Scaphe Dial of Georg Hartmann, 1548, Collection of Historical Scientific Instruments, Harvard University (Cambridge, Masachusetts). 10. Elliptic Compass, from Ettore Ausonio, Letter to Annibale Bichi, Biblioteca Comunale degl’ Intronati (Siena), L. VI. 10, 29 September 1545, f. 92r. 11. Letter Cover Addressed to Ausonio at the Workshop of Michele Tramezzino, from Ettore Ausonio, Biblioteca Ambrosiana (Milan), G 120 Inf., f. 74v. 12. Michele Tramezzino, Map of the World, Western Hemisphere (Detail), 1554, from University Library (Leiden), Collection Bodel Nijenhuis, 002-05-002. 13. Sebastian Cabot, Map of the World, 1544, from Bibliothèque Nationale de France (Paris), Département des Cartes et Plans, Res. Ge. Aa. 582. 14. Sebastian Cabot, Map of the World (Detail), 1544, from Bibliothèque Nationale de France (Paris), Département des Cartes et Plans, Res. Ge. Aa. 582. 15. Ettore Ausonio, Volvelle Dedicated to the Duke of Savoy, 1563, B. A. M., D 178 Inf., f. 25r. 16. Ettore Ausonio, Classification of the Sciences, B. A. M., G 121 Inf., f. 16v. 17. Ettore Ausonio, Table of Refractions of a Refractive Scaphe Dial for the Latitude of 48°, Biblioteca Ambrosiana (Milan), D 178 Inf., ff. 88r-88v. 18. Ettore Ausonio, Table of Refractions of a Refractive Scaphe Dial for the Latitude of 45°, Biblioteca Ambrosiana (Milan), D 178 Inf., ff. 82v. 19. Ettore Ausonio, Witelo’s Table of Refractions, B. A. M., D 178 Inf., f. 73v. 20. Ettore Ausonio, Calculations of Angles of Refraction, B. A. M., D 178 Inf., f. 74r. V List of Illustrations 21. Ettore Ausonio, Calculations of Angles of Refraction, B. A. M., D 178 Inf., f. 74v. 22. Ettore Ausonio, Calculations of Angles of Refraction, B. A. M., D 178 Inf., f. 79v. Chapter IV. The Point of Inversion in Sixteenth Century Optics: The ‘Theory of the Concave Spherical Mirror’ of Ettore Ausonio. 1. Cathetus Rule for Plane Mirrors. 2. Cathetus Rule for Curved Mirrors. 3. Cathetus Rule for Refraction. 4. Attempt at Finding the Law of Refraction by the Localistation of the Image, from Johannes Kepler, Paralipomena ad Vitellionem, 1604, p. 86. 5. Kepler’s Proof of the Limited Applicability of the Cathetus Rule. 6. Kepler’s Disproval of the Cathetus Rule for the Localisation of an Image in a Convex Mirror. 7. Image Location in a Refractive Sphere with Two Eyes, from Johannes Kepler, Paralipomena ad Vitellionem, 1604, p. 179. 8. Kepler’s Determination of the Focus of a Refractive Sphere. 9. Image Location in a Refractive Sphere – Kepler’s Imago, from Johannes Kepler, Paralipomena ad Vitellionem, 1604, p. 192. 10. Ettore Ausonio, Burning Mirror, Biblioteca Ambrosiana (Milan), G 120 Inf., f. 4r. 11. Galileo Galilei, Theorica, Biblioteca Nazionale (Florence), Gal. 83, f. 4r. 12. Sarpi’s Copy of Ausonio’s Theorica, from Paolo Sarpi, Manoscritto dell’ Iride e del Calore, Bibliotheca Marciana (Venice), It. II, 129 (= 4914), f. 303r. 13. Giovanni Antonio Magini, Theorica Speculi Concavi Sphaerici (Detail), 1602. 14. Image Location in a Concave Spherical Mirror, from Witelo, Opticae Thesaurus, p. 355. 15. Burning Mirror, from Pseudo-Euclid, Catoptrics, proposition 30. 16. Burning Mirror, from Pseudo-Euclid, Catoptrics, proposition 30. 17. Determination of the Focal Point of a Concave Spherical Mirror, from Alhazen, A Discourse on the Concave Spherical Mirror, proposition 3. 18. Concave Spherical Burning Mirror, from Witelo, Opticae Thesaurus, p. 366. 19. Ettore Ausonio, Focal Point of a Concave Spherical Mirror, from Biblioteca Ambrosiana (Milan), D 117 Inf., f. 142v. 20. Octogonal Ray and Spherical Aberration in Ausonio’s Theorica. 21. Image Formation in a Concave Spherical Mirror with the Eye and the Object between the Focal Point and the Center of Curvature, from Pseudo-Euclid, Catoptrics, proposition 28. 22. Image Formation in a Concave