AND THEORY OF THE HEAVENS. 109 



All the other members whose rotation is known incline 

 their axes to the plane of their orbits ; Saturn more than 

 the others, but the Earth more than Mars, whose axis is 

 also directed almost perpendicular to the ecliptic. 1 The 

 equator of Saturn (in so far as we may regard it as indicated 

 by the direction of its ring) is inclined to the plane of its 

 path at an angle of 31 degrees, while the Earth has an 

 inclination to its path of 22 \ degrees. 2 The cause of 

 these deviations may perhaps be referred to inequality 

 in the movements of the matter which has been con- 

 joined to form the planet. The principal movement of 

 the particles in the direction of the plane of its orbit, was 

 around the centre of the planet; and the common 

 plane lay there around which the elementary particles 

 accumulated to make the movement circular there if 

 possible, and to accumulate matter for the formation of 

 the satellites, which, on that account, never deviate far 

 from the plane of the orbit. If the planet formed itself 

 for the most part only out of these particles, its axial 

 rotation at its first formation would have diverged as 

 little from it as the satellites do; but it formed itself, as 

 the theory has shown, more out of the particles which 

 sank to it from both sides, and the quantity or velocity 

 of which seems not to be so completely balanced as that 

 the one hemisphere should not have been able to get a 

 slight excess of movement over the other, and therefore 

 acquire a certain deviation of the axis. 



Notwithstanding these reasons, I present this explanation 

 only as a conjecture, which I do not pretend to have 

 established. My real opinion amounts to this : that the 



1 Mars has an inclination of about 29 degrees. Tr. 



- Saturn's inclination is 26 49'; that of the Earth 23 27'. Tr. 



