BiOKERTON. — On the Origin of the Solar System. 155 



difficulty, that nothing but a nearer and nearer ai^proxiniation is to be ex- 

 pected. It is this opinion that must be my apology for bringing before the 

 society the somewhat crude suggestions of this paper. 



Each of the hypotheses already mentioned assumes a previously 

 existing rotating mass, extending beyond the orbit of Neptune. The 

 papers already before the society distinctly show that a tangential collision 

 between two cosmical bodies could certainly develope such a mass. 

 A paper now in preparation on the origin of cosmical rotation is intended 

 to exhibit some of these points more clearly, so that should future investi- 

 gation ever reconcile the present difficulties of either of the above theories 

 and cause their ultimate acceptance, there will still remain a probability 

 that the original rotating mass was produced by the " partial impact " of 

 two cosmical bodies. 



The common direction of all the planets in their orbits, and the common 

 direction of rotation of most of them, and the slight inclination of their 

 orbital plane, unmistakeably point to a common origin of the sun and 

 planets ; while the eccentricity of the orbits, the slight difference of the 

 orbital planes, the inclination of the axes and of the orbital planes of their 

 satellites, and the retrogade motion of some, all point to some independent 

 specific structure for each planet due to motions and structure existing 

 before the common constructive agent had become effective, and not un- 

 likely independent of that cause. 



At the present stage of the enquiry there appear to be only two 

 varieties of impact which do not possess insuperable objections, the 

 most probable being that the solar system was formed by a moderately 

 complete impact, and subsequent entire coalescence, of two very rare 

 bodies possessing considerable proper motion, each of which had rotat- 

 ing around it in varied azimuths a number of bodies such as constitute 

 the zodiacal light ; but among them were some of planetary dimensions. It 

 is not difficult to show how such bodies themselves may have originated. 



This impact may have resulted in the w^hole of the two bodies spreading 

 out into a large disk-shaped rotating nebula, ultimately extending beyond 

 Neptune, with the separate bodies revolving around and through it. It is 

 evident that any body revolving around another has a higher kinetic 

 energy than an equal mass of the central body, as it has the energy of the 

 general motion and also that of its revolution in its orbit, consequently, 

 during impact, these bodies will pass away in advance of the nebula ; but, 

 on return, wiU be subject to all the agents tending to render the orbit 

 ch'cular that are discussed in the last paper. 



It will be easily seen that supposing the satellites were originally revolving 

 around the two bodies in all planes, at the impact the motion developed by 



