548 Transactions. — Miscellaneous. 



Molecular Selective Escape. 



22. Immediately after the impact the temperature of 

 different kinds of molecules will be very different from one 

 another. Were the two colliding spheres composed of oxygen, 

 they would be sixteen times as hot as if they were similar 

 spheres of hydrogen. The temperature at impact will be 

 proportional to the atomic weight. In a sphere of mixed 

 elements these inequalities of temperature would quickly 

 equalize themselves. When this was the case the hydrogen 

 would be moving four times as fast as the oxygen. The 

 velocities would vary inversely as the square root of the 

 atomic weights. 



23. This difference of velocity will tend to sort the mole- 

 cules into layers like those of a lily bulb. The hydrogen on 

 the outside will be followed by lithium and other elements in 

 the order of their atomic weights. 



24. If there are elements lighter than hydrogen, as spec- 

 troscopic observations of the corona suggest, these will, of 

 course, precede hydrogen. In my lectures and papers on this 

 subject I have called this action "molecular selective 

 escape." 



25. Space will be thickly spread with free molecules of the 

 lightest elements. This fact is important : it is one of the 

 counteracting agencies that prevent the theory of the dissipa- 

 tion of energy being of cosmic application. 



26. A telescopic view of a new planetary nebula produced 

 by a partial impact, if seen through a prism, should give a 

 series of discs of diameters diminishing with increase of atomic 

 weight in its component elements. 



27. This fact, taken in conjunction with the broa.dening 

 of the lines into bands, will enable us to calculate the distance 

 of such a body. It is possible, however, that the parallelism 

 of the motion of the foremost molecules may prevent encoun- 

 ters ; hence this layer of gas may not be luminous. 



Formation of Star-clusters and Meteoric Swarms. 



28. The hydrogen will rob the heavy molecules of their 

 energy : hence in any considerable graze the heavy metals 

 might not indefinitely expand. They would lose their velocity 

 by radiation and by doing work against gravitation, and they 

 would be attracted back again, and may form a star in the 

 centre of the nebula. Some nebuhe have such stars. 



29. In a partial impact the coalesced part will not have all 

 its motion converted into heat. The momentum on the two 

 sides will not be exactly balanced. The body will consequently 

 tend to spin. It is generic of partial impact that it tends to 

 cause rotation in all the bodies produced, and also that the 

 rotation is all in the same direction. 



