~CHAP. 3.~ _Of the motion of the moon and the other secondary planets_ _That they are influenced by a centripetal force directed toward their primary, as the primary are influenced by the sun_ p. 182 _That the power usually called gravity extends to the moon_ p. 189 _That the sun acts on the secondary planets_ p. 190 _The variation of the moon_ p. 193 _That the circuit of the moons orbit is increased by the sun in the quarters, and diminished in the conjunction and opposition_ p. 198 _The distance of the moon from the earth in the quarters and in the conjunction and opposition is altered by the sun_ p. 200 _These irregularities in the moon’s motion varied by the change of distance between the earth and sun_ p. 201 _The period of the moon round the earth and her distance varied by the same means_ ibid. _The motion of the nodes and the inclination of the moons orbit_ p. 202 _The motion of the apogeon and change of the eccentricity_ p. 218 _The inequalities of the other secondary planets deducible from these of the moon_ p. 229 ~CHAP. 4.~ _Of comets_ _They are not meteors, nor placed totally without the planetary system_ p. 230 _The sun acts on them in the same manner as on the planets_ p. 231 _Their orbits are near to parabola’s_ p. 233 _The comet that appeared at the end of the year 1680, probably performs its period in 575 years, and another comet in 75 years_ p. 234 _Why the comets move in planes more different from one another than the planets_ p. 235 _The tails of comets_ p. 238 _The use of them_ p. 243 244 _The possible use of the comet it self_ p. 245 246 ~CHAP. 5.~ _Of the bodies of the sun and planets_