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CONTENTS.

INTRODUCTION ... ... ... ... ... ... ... viii
SUMMARY OF THE PART OF THE OPUS TERTIUM HERE
    PRINTED ... ... ... ... ... ... ... xxxi
PART OF THE OPUS TERTIUM—
  On the Utility of Mathematics for Directing the Commonwealth original: "De Utilitate Mathematice ad Rem Publicam dirigendam" ... ... ... ... ... ... ... 1
    On the foundations of astrological judgments ... ... ... ... 5
    On the locations of the world ... ... ... ... ... ... 9
    On promoting good and hindering evil ... ... ... 13
  On Optics original: "De Perspectiva". In the Middle Ages, "perspective" referred to the science of sight and light. ... ... ... ... ... ... ... 20
    On the ten necessities required for sight, chapter 1 ... 24
    On visible things, which are distinguished into twenty-two types,
    chapter 2 ... ... ... ... ... ... ... 26
    On the particular modes of seeing, chapter 3 ... ... ... 28
    On the excellence of sight, chapter 4 ... ... ... ... 29
    On the three universal modes of seeing, chapter 5 ... ... 30
    On the knowledge of a seen thing through logical deduction, chapter 6 original: "per sillogismum" ... ... 32
    On the three parts of optics, chapter 7 ... ... ... 34
    On sight occurring through a refracted line, chapter 8 ... ... ... 37
    On the comparison of science to wisdom, chapter 9 ... ... 40
  On Experimental Science original: "De Scientia Experimentorum". This was Bacon's term for a science based on observation and tested experience. ... ... ... ... ... 43
    On the science of the fifth essence original: "quinte essentie". This refers to the quintessence or ether, the material of the heavenly bodies in medieval physics. ... ... ... ... ... 47
  On Moral or Civil Science ... ... ... ... ... 55
    On the second part of moral science ... ... ... ... 57
    On the third part of moral philosophy ... ... ... ... 59
    On the fourth part of moral philosophy ... ... ... ... 61
    On the fifth part of moral philosophy ... ... ... ... 75
  On the Lesser Work original: "De Opere Minori" ... ... ... ... ... ... ... 77
  On the Riddles of Alchemy ... ... ... ... ... ... 80
    On the explanation of the riddles of alchemy ... ... ... ... 83
    On the keys of alchemy ... ... ... ... ... ... 86