TO BE DIVIDED INTO EQUAL AREAS 68

31. MODE OF DRAWING AN ELLIPSE 70

32. KEPLER'S DIAGRAM PROVING EQUABLE DESCRIPTION OF AREAS
FOR AN ELLIPSE 71

33. DIAGRAM OF A PLANET'S VELOCITY IN DIFFERENT PARTS OF ITS ORBIT 72

34. PORTRAIT OF KEPLER 76

35. CURVE DESCRIBED BY A PROJECTILE 82

36. TWO FORMS OF PULSILOGY 87

37. TOWER OF PISA 91

38. VIEW OF THE HALF-MOON IN SMALL TELESCOPE 97

39. PORTION OF THE LUNAR SURFACE MORE HIGHLY MAGNIFIED 98

40. ANOTHER PORTION OF THE LUNAR SURFACE 99

41. LUNAR LANDSCAPE SHOWING EARTH 100

42. GALILEO'S METHOD OF ESTIMATING THE HEIGHT OF LUNAR MOUNTAIN 101

43. SOME CLUSTERS AND NEBULAE 102

44. STAGES OF THE DISCOVERY OF JUPITER'S SATELLITES 103

45. ECLIPSES OF JUPITER'S SATELLITES 105

46. OLD DRAWINGS OF SATURN BY DIFFERENT OBSERVERS, WITH
THE IMPERFECT INSTRUMENTS OF THAT DAY 111

47. PHASES OF VENUS 112

48. SUNSPOTS AS SEEN WITH LOW POWER 113

49. A PORTION OF THE SUN'S DISK AS SEEN IN A POWERFUL MODERN
TELESCOPE 114

50. SATURN AND HIS RINGS 115

51. MAP OF ITALY 118

52. PORTRAIT OF GALILEO 126

53. PORTRAIT OF DESCARTES 148

54. DESCARTES'S EYE DIAGRAM 151

55. DESCARTES'S DIAGRAM OF VORTICES FROM HIS "PRINCIPIA" 152

56. MANOR-HOUSE OF WOOLSTHORPE 162

57. PROJECTILE DIAGRAM 170

58. } { 171
59. } DIAGRAMS ILLUSTRATIVE OF THOSE NEAR THE BEGINNING { 174
60. }