CHAPTER VII.

KEPLER (FROM 1571 A.D. TO 1630 A.D.), §§ 135-151 179-197

§ 135. Early life and theological studies 179

§ 136. Lectureship on mathematics at Gratz: astronomical studies and speculations: the _Mysterium Cosmographicum_ 180

§ 137. Religious troubles in Styria: work with Tycho 181

§ 138. Appointment by the Emperor Rudolph as successor to Tycho: writings on the new star of 1604 and on Optics: theory of refraction and a new form of telescope 182

§ 139. Study of the motion of Mars: unsuccessful attempts to explain it 183

§§ 140-1. The _ellipse_: discovery of the first two of _Kepler’s Laws_ for the case of Mars: the _Commentaries on Mars_ 184

§ 142. Suggested extension of Kepler’s Laws to the other planets 186

§ 143. Abdication and death of Rudolph: appointment at Linz 188

§ 144. The _Harmony of the World_: discovery of _Kepler’s Third Law_: the “music of the spheres” 188

§ 145. _Epitome of the Copernican Astronomy_: its prohibition: fanciful correction of the distance of the sun: observation of the sun’s _corona_ 191

§ 146. Treatise on _Comets_ 193

§ 147. Religious troubles at Linz: removal to Ulm 194

§ 148. The _Rudolphine Tables_ 194

§ 149. Work Under Wallenstein: death 195

§ 150. Minor discoveries: speculations on gravity 195

§ 151. Estimate of Kepler’s work and intellectual character 197