~CHAP. 4.~ _Of the resistance of fluids_ p. 143 _Bodies are resisted in the duplicate proportion of their velocities_ p. 147 _Of elastic fluids and their resistance_ p. 149 _How fluids may be rendered elastic_ p. 150 _The degree of resistance in regard to the proportion between the density of the body and of the fluid_ _In rare and uncompressed fluids_ p. 153 _In compressed fluids_ p. 155 _The degree of resistance as it depends upon the figure of bodies_ _In rare and uncompressed fluids_ p. 155 _In compressed fluids_ p. 158 BOOK II. ~CHAP. 1.~ _That the planets move in a space empty of sensible matter_ p. 161 _The system of the world described_ p. 162 _The planets suffer no sensible resistance in their motion_ p. 166 _They are not kept in motion by a fluid_ p. 168 _That all space is not full of matter without vacancies_ p. 169 ~CHAP. 2.~ _Concerning the cause that keeps in motion the primary planets_ p. 171 _They are influenced by a centripetal power directed to the sun_ p. 171 _The strength of this power is reciprocally in the duplicate proportion of the distance_ ibid. _The cause of the irregularities in the motions of the planets_ p. 175 _A correction of their motions_ p. 178 _That the frame of the world is not eternal_ p. 180