§ 128. =Dialogue on the Two Chief Systems of the World.= Its preparation and publication 162 § 129. The speakers: argument for the Coppernican system based on the telescopic discoveries: discussion of stellar parallax: the _differential method of parallax_ 163 § 130. Dynamical arguments in favour of the motion of the earth: the _First Law of Motion_. The tides 165 § 131. =The trial and condemnation.= The thinly veiled Coppernicanism of the _Dialogue_: the remarkable preface 168 § 132. Summons to Rome: trial by the Inquisition: condemnation, abjuration, and punishment: prohibition of the _Dialogue_ 169 § 133. Last years: life at Arcetri: _libration_ of the moon: the _Two New Sciences_: _uniform acceleration_, and the first law of motion. Blindness and death 172 § 134. Estimate of Galilei’s work: his scientific method 176 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