BiOKEBTON. — On the Origin of the Visible Universe. 179 



go quite so far as to suppose the body cold. I sliall assume two stupendous 

 bodies, having small independent proper motion in space, being probably at 

 exceedingly high temperatures, endowed with a considerable rotation, and 

 having a large number of bodies revolving around them, and not unlikely 

 making up a considerable proportion of their mass. The probable existence 

 of such bodies is rendered likely on the view of the cosmogony which 

 follows as a logical deduction from the conception of partial impact. 



I will now place before you some of the broader conclusions which are 

 general deductions to all cases of partial impact : — 



1st. The original independent motion of the bodies acts in three ways — 

 (a) it tends to render the impact more partial ; (b) in those parts coming into 

 impact, it increases the temperature ; and (c) it tends to increase resultant 

 velocity, and hence the escape of the several pieces. 



2nd. At impact, all parts coming into actual collision will have a part 

 of their molar motion converted into heat, and the more completely the 

 parts coming into impact destroy each other's momentum, the higher the 

 temperature of those parts. On the other hand, as those parts will possess 

 no molar motion they will tend at first to occupy the centre of the mass. 



3rd, In partial impact the whole motion (except that due to original 

 rotation and to pressure) will tend to lie in the plane containing the line 

 joining the centres of gravity, and containing the direction of motion of 

 the two bodies at impact. This plane is doubtless the great circle bisecting 

 the milky way, and might be considered the ecliptic of sidereal astronomy. 



4th. A tendency to rotation must be produced which at first will be 

 generally in one direction. This may pass through an ajDparent irregularity, 

 but finally, on the condensation of the mass, some would exist. 



5th. After some time has elapsed, the whole of the motion being 

 originally nearly radial, and chiefly occupying one plane, will tend to 

 develope an irregular ring consisting of several roughly si^u'al masses. 



6th. All original rotation, both of bodies in orbits and of the large 

 masses themselves, will tend to destroy the symmetry of the ring, and to 

 take the matter from its plane. 



7th. Generally, considerable irregularities in matter not uniformly 

 spread will tend to increase themselves. Thus, if a hole appears in an 

 infinite flat disc, attraction will tend to make it greater ; and again, a break 

 in a ring will tend to increase in width, the ring itself tending, of course, to 

 diminish its mean diameter. 



8th. The chief of the molecular motion (heat) will act radially in all 

 directions, and consequently will change the disc (which resultant motion of 

 mass tends to develope) into a lenticular mass. 



9th. The varying velocity of different chemical substances at the same 

 temperature, when acted on by gravity, will tend to separate this lens into 



