BiCKERTON. — Evidence in favour of Impact. 475 



result. Such a nebula would be unstable. Croll's theory to 

 account for an increase in the age of the sun's heat by the 

 impact of two suns is therefore untenable. 



The Cosmos possibly Immortal. 



67. If our universe be proved from its form and character 

 to have been formed of two previously-existing universes, as 

 appears probable from 56, et seq., then the entire cosmos may 

 be made up of an infinity of universes. 



68. Meteoric swarms prove space to be dusty with wan- 

 dering dark bodies, and " selective escape " proves it also to 

 be spread with countless myriads of molecules of light gas. 

 It is probably due to the dust of space that we see no distant 

 universes other than the Magellanic Clouds, 



69. If this be the case, radiation must all be caught by the 

 dust of space, and, unless some agency be found to take this heat 

 away, the dust must be gradually increasing in temperature. 



70. Bodies not in orbits occupy but a short time at high 

 velocity. They occupy longer and longer periods as the velo- 

 city is reduced. Hence hydrogen gas, independent of matter, 

 will be generally moving slowly. But slowly -moving gas is cold : 

 hence hydrogen gas may be at a lower temperature than any 

 other matter in spa,ce. 



71. Whenever, by their mutual motions, hydrogen strikes 

 cosmic dust it will acquire the temperature of the latter — that 

 is, it will increase its molecular velocity. It will thus have a 

 new start of motion. 



72. Unless it strikes something, the molecule can only lose 

 this motion by radiation, or by doing work. When it has done 

 work it will be further from matter, or in a position of higher 

 potential ; and Crooks's experiments prove that molecules do 

 not radiate in free path excepting after encounters. 



73. Moving matter not in orbits will tend to move most 

 slowly where there is least matter — that is, where gravitation 

 potential is highest — because in these places it has done most 

 work against gravitation. Where bodies moving indiscrimi- 

 nately move most slowly they obviously tend to aggregate : in 

 other words, the hydrogen of space tends to accumulate in the 

 sparsest portions of space. 



74. Thus radiant energy falls on the dust of space, and 

 heats it. This heat gives motion to hydrogen, and the hydro- 

 gen then tends to use its new energy to pass to positions of 

 high potential, thus converting low-temperature heat — that is, 

 dissipated energy — into potential energy of gravitation — that 

 is, into the highest form of available energy. 



75. This action will tend to go on until attraction is equal 

 in different parts of space ; but then we have in one part of 

 space bodies in mass, in another diffused hydrogen. 



