THE CHEMISTRY OF THE STARS. 177 



off' and fill the interspaces. As condensation goes on, the temperature 

 at the center of condensation always increasing, all the meteorites in 

 time are driven into a state of gas. The meteoritic bombardment prac- 

 tically now ceases for lack of material, and the future history of the 

 mass of gas is that of a cooling body, the violent motions in the atmos- 

 phere while condensation was going on now being replaced by a rela- 

 tive calm. 



The absorption phenomena in stellar spectra are not identical at the 

 same mean temperature on the ascending and descending sides of 

 the curve, on account of the tremendous difference in the physical 

 conditions. 



In a condensing swarm, the center of which is undergoing meteoritic 

 bombardment from all sides, there can not be the equivalent of the 

 solar chromosphere; the whole mass is made up of heterogeneous vapor 

 at different temperatures and moving with different velocities in dif- 

 ferent regions. 



In a condensed swarm, of which we can take the sun as a type, all 

 action produced from without has practically ceased; we get relatively 

 a quiet atmosphere and an orderly assortment of the vapors from top 

 to bottom, disturbed only by the fall of condensed metallic vapors. 

 But still, on the view that the differences in the spectra of the heavenly 

 bodies chiefly represent differences in degree of condensation and tem- 

 perature, there can be, au fond, no great chemical difference between 

 bodies of increasing and bodies of decreasing temperature. Hence we 

 find at equal mean temperatures on opposite sides of the temperature 

 curve this chemical similarity of the absorbing vapors proved by many 

 points of resemblance in the spectra, especially the identical behavior 

 of the enhanced metallic and cleveite lines. 



CELESTIAL DISSOCIATION. 



The time you were good enough to put at my disposal is now exhausted, 

 but I can not conclude without stating that I have not yet exhausted 

 all the conceptions of a high order to which Fraunhofer's apparently 

 useless observation has led us. 



The work which to my mind has demonstrated the evolution of the 

 cosmos as we know it from swarms of meteorites, has also suggested a 

 chemical evolution equally majestic in its simplicity. 



A quarter of a century ago I pointed out that all the facts then avail- 

 able suggested the hypothesis that in the atmospheres of the sun and 

 stars various degrees of "celestial dissociation "were at work, a u disso- 

 ciation" which prevented the coming together of the finest particles of 

 matter which at the temperature of the earth and at all artificial tem- 

 perature yet attained here compose the metals, the metalloids and 

 compounds. 



On this hypothesis the so called atoms of the chemist represent not 

 the origins of things, but only early stages of the evolutionary process. 

 SM 98 12 



