Contents xvii 



CHAPTER VI. 



VAGE 



GALILEI (FROM 1564 A.D. TO 1642 A.D.), 113-134 . 145-178 



113. Early life 145 



114. The pendulum 146 



115. Diversion from medicine to mathematics: his first 



book 146 



1 16. Professorship at Pisa : experiments on falling 

 bodies: protests against the principle of 



authority 147 



117. Professorship at Padua: adoption of Coppernican 



views 148 



118. The telescopic discoveries. Invention of the tele- 

 scope by Lippersheim : its application to 

 astronomy by Harriot, Simon Marius, and 



Galilei . 149 



119. The Sidereus Nuncius: observations of the moon 150 



120. New stars: resolution of portions of the Milky 



Way 151 



121. The discovery of Jupiter's satellites : their im- 

 portance for the Coppernican controversy : 

 controversies .... 151 



122. Appointment at the Tuscan court . . . 1 53 

 123. Observations of Saturn. Discovery of the 



phases of Venus . . ... . . 154 



124. Observations of sun-spots by Fabricius, Harriot, 



Scheiner, and Galilei : the Macchie Solan : 

 proof that the spots were not planets : obser- 

 vations of the umbra and penumbra . . 154 

 125. Quarrel with Scheiner and the Jesuits : theological 

 controversies: Letter to the Grand Duchess 



Christine 157 



126. Visit to Rome. The first condemnation : prohibition 



of Coppernican books 159 



127. Method for finding longitude. Controversy on 



comets: // Saggiatore ...... 160 



128. Dialogue on th^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 



b 



