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Galileo: Pioneer Scientist

Stillman Drake
Copyright Date: 1990
Pages: 261
  • Book Info
    Book Description:

    With this book Drake confirms Galileo as the first recognizably modern scientist, in both his methods and results.

    eISBN: 978-1-4426-5992-6
    Subjects: History, History of Science & Technology, Physics, General Science

Table of Contents

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  1. Front Matter
    (pp. i-vi)
  2. Table of Contents
    (pp. vii-viii)
  3. Figures
    (pp. ix-x)
  4. Preface
    (pp. xi-2)
  5. Introduction
    (pp. 3-8)

    Einstein once advised us that in seeking to understand the thought of a creative scientist, we should pay attention not just to what he says, but to what he does. What Galileo did is known mainly from surviving notes found on pages containing diagrams and calculations but few or no words. What he said in books was based upon what he had done, but was frequently misinterpreted as long as we had only spotty information about the work that lay behind his words. In astronomy, what Galileo had done was told in his reports of telescopic observations and discoveries, except...

  6. CHAPTER ONE The Laws of Pendulum and Fall
    (pp. 9-31)

    Galileo’s working papers on motion from 1602 to 1637, when hisTwo New Scienceswent to the publishers, are now bound into volume 72 of the Galilean manuscripts at Florence. On f. 107v of that volume are the first surviving measurements of distances that he recorded. They were inpunti, though no unit was named on that page, which contained nothing except numbers and diagrams. A few days later the same measurements became linked with the law of fall, so let us begin with f. 107v. On that page are found measurements made with a ruler, probably brass, finely divided...

  7. CHAPTER TWO The Medieval Context
    (pp. 32-43)

    Galileo’s law of fall was an anachronism in 1604. As is evident from the preceding chapter, its historical background need not be known in order to understand the work that put the law into Galileo’s hands. Hence the present chapter is in the nature of an interlude that may be skipped over without effect on the biographical contents of the main text.¹

    The medieval concept of impetus, by which fourteenth-century natural philosophers had arrived at a different mathematical rule for distances and speeds in fall, was certainly known to Galileo when he began his study of natural motions. Impetus theory...

  8. CHAPTER THREE Galileo’s Pre-Paduan Doctrine of Motion
    (pp. 44-57)

    Galileo entered the University of Pisa as a student in 1581, remaining there four years. At first he studied medicine, but in 1583 he became more interested in mathematics and natural philosophy (as physics was traditionally called). He left without a degree, and during the years 1585 to 1589 he tutored privately at Florence and at Siena. At Siena, in the academic year 1586–7, he also held a public teaching post. From 1589 to 1592 Galileo was professor of mathematics at his alma mater, with the obligation of teaching Ptolemaic astronomy and Euclid’sElements.

    In 1584, while still a...

  9. CHAPTER FOUR The Ancient Greek Background
    (pp. 58-69)

    In chapter 2 the medieval historical context of the law of fall was outlined, including Buridan’s sophisticated causal account of fall in terms of impetus theory. That did not lead to the times-squared law, and indeed it was revived and revised to refute the law as poor physics soon after Galileo died. There had been, however, a much more ancient attempt to direct physics along the line eventually taken by Galileo, around 150 bc, and Galileo himself had started out along that ancient road before he learned that it had been opened in Greek antiquity – only to be promptly...

  10. CHAPTER FIVE Mechanics, Tides, and Copernicanism
    (pp. 70-82)

    It is hardly to be doubted that when Galileo moved to Padua late in 1592 he intended to publish there, or at nearby Venice, his new doctrine of motion and his revised commentaries on theAlmagestpresenting the semi-Copernican system of astronomy and cosmology. Expiration of his contract at the University of Pisa had removed any advantage he could gain by publication there or at Florence, whereas the fame he expected from the astronomy he believed to be original would cement him in his new and better-paid professorship at Padua. Yet neither manuscript was ever published, and Galileo’s interest turned...

  11. CHAPTER SIX Cosmology, Mechanics, and Motion
    (pp. 83-98)

    It was said earlier that as soon as Galileo had composedDe systemate mundiin 1600–1 he returned to mechanics, writing a treatise known by that title toward the end of 1601. At its end he alluded to a treatise on problems of mechanics appended to it, which has not survived. There is little doubt that it was an Italian version of his Latin lectures at the university in 1598–9 commenting on the ancient GreekProblems of Mechanics. Probably he had added some practical problems, for the first section of hisMechanicswas ‘On Useful Things That Are...

  12. CHAPTER SEVEN Natural Motion and Horizontal Projection
    (pp. 99-115)

    Discovery of the laws of the pendulum and of fall, with the latter verified as also applicable to descent from rest along an inclined plane, opened the year 1604 for Galileo as one of great activity recorded in his working papers. In October he wrote out for Paolo Sarpi his first attempted derivation of the law of fall from an assumed principle. Precisely at that time a supernova appeared that diverted his attention to astronomy. Discussion of that interruption will be deferred to the next chapter on astronomy.

    Work done immediately after the 1604 discovery, still on f. 189, was...

  13. CHAPTER EIGHT Oblique Projection; Other Physics
    (pp. 116-129)

    In the summer of 1608 Galileo was requested to journey to Florence but appears to have wished to remain at Padua, though for several years he had spent the summer at Florence. He was, however, virtually commanded by the Grand Duchess Christina to be present at the wedding of the young Prince Cosimo, to whom Galileo had dedicated his book on the geometric and military compass in 1606. From the handwriting on the working papers of 1608, it appears to me that he had just finished f. 116v and begun his analysis of horizontal projections when he left for Florence,...

  14. CHAPTER NINE Astronomy and the Telescope
    (pp. 130-144)

    Galileo’s work on motion was interrupted for a time in 1604–5 by the appearance of a supernova in October, just as he was writing out for Palo Sarpi the first attempted derivation of the law of fall. Because the events bear on Galileo’s Copernicanism, and are not at all widely known, it will be appropriate to review them before taking up the story of his telescopic discoveries.

    A conjunction of Jupiter and Mars was predicted for 8 October 1604 by tables then in use by astronomers, and many throughout Europe were observing the skies that night. The conjunction did...

  15. CHAPTER TEN The Telescope and Copernicanism
    (pp. 145-163)

    The most compelling evidence that Galileo was ever to have for the correctness of the Copernican annual motion of the earth was his success in predicting eclipses of Jupiter’s satellites. He never mentioned that evidence except in an appendix to his letters on sunspots published at Rome in 1613. Galileo did not become aware of the existence of satellite eclipses until July 1612, so it may appear anachronistic to mention it at this point. But its relevance is twofold: first, the principal defect of the pioneer tables of satellite motions begun at Rome on 1 April 1611 arose from Galileo’s...

  16. CHAPTER ELEVEN Hydrostatics, Philosophers, and Religion
    (pp. 164-177)

    Galileo returned to Florence from Rome in June 1611 and was soon drawn into a controversy with professors of natural philosophy at the University of Pisa. The place was the palazzo of Filippo Salviati, a young patrician who invited Galileo to join scholars meeting occasionally at his home to discuss various topics of interest to Salviati, whose education had consisted largely of self-imposed reading. Galileo held him in the highest regard for his intelligence and learning. Salviati died in 1614 during a visit to Spain; he was immortalized as spokesman for the views of Galileo in his later books written...

  17. CHAPTER TWELVE Comets, the Church, and Tides
    (pp. 178-191)

    Robert Southwell, who was later to become president of the Royal Society, visited Vincenzio Viviani at Florence in 1661 and recorded a number of his anecdotes about Galileo. Among them was the following:

    He used to say that if he were to live 1,000 years, and still expected to understand the doctrine of meteors rightly, he would consider himself the greatest fool who ever attained that age.

    By ‘the doctrine of meteors’ was meant material of the kind that Aristotle had written separately from cosmology and physics, in the book calledMeteorologicorum, dealing with a variety of phenomena in the...

  18. CHAPTER THIRTEEN Concerning Galileo’s Dialogue
    (pp. 192-206)

    A preface addressed ‘to the discreet reader’ that opens the famousDialoguehas puzzled every modern critic, and perhaps many readers at its time. It began:

    Several years ago there was published at Rome a salutary edict which, in order to obviate dangerous tendencies of our present age, imposed a seasonable silence upon the Pythagorean opinion that the earth moves. There were those who imprudently asserted that this decree had its origin not in judicious inquiry, but in passion none too well-informed. Complaints were heard that advisers who were totally unskilled at astronomical observations should not clip the wings of...

  19. CHAPTER FOURTEEN Two New Sciences
    (pp. 207-220)

    While Galileo was at Rome awaiting trial he received an invitation from Archbishop Ascanio Piccolimini of Siena to visit him on his way back to Florence. Galileo was emotionally disturbed after hearing the sentence pronounced against him. The Tuscan ambassador applied immediately to the pope for pardon, or at the least for commutation of sentence so that Galileo would not be held in the dungeons of the Roman inquisition. The pope agreed to allow Galileo to proceed as far as Siena, to remain there in custody of the archbishop pending further instructions. It was there that he began writingTwo...

  20. CHAPTER FIFTEEN From Galileo to Newton
    (pp. 221-234)

    In my reconstruction of Galileo’s thought as a physicist, he abandoned the concept of an ‘impressed force’ as a cause of motion in 1598 and never returned to it. Except for his writings on motion before he moved to Padua, they are all kinematic, or at most kinetic, in conception. The concept of force, or of energy, remained undefined, as shown by Galileo’s treatise on the force of impact (or of percussion as he called it). Written in his last years and intended for inclusion inTwo New Sciences, that was withheld and never printed until 1718, long after his...

  21. CHAPTER SIXTEEN Galilean Units Today
    (pp. 235-248)

    From the time of Newton to the present century, advancement of physics depended mainly on dynamic investigations. Study of motion for its own sake, pioneered by Galileo, gave way to study of forces when dynamics was created. Until 1905, when Einstein proposed his special theory of relativity, kinematics had fallen into relative neglect. The title of Einstein’s paper hardly even hinted that both the concept of simultaneity and the measurement of time required fundamental revision, for that title was simply ‘Electrodynamics of moved bodies.’ Yet that paper inaugurated a renaissance of kinematics because Einstein re-examined elementary concepts at a highly...

  22. Bibliography
    (pp. 249-256)
  23. Index
    (pp. 257-261)