SCIENCE AND RELIGION 153 



ing in extent, condensation, brightness, general form, 

 possession of nuclei, situation, and in resemblance to 

 comets and to stars. They ranged from a faint trace 

 of extensive diffuse nebulosity to a nebulous star with 

 a mere vestige of cloudiness. Herschel was able to 

 make the series so complete that the difference be- 

 tween the members was no more than could be found 

 in a series of pictures of the human figure taken from 

 the birth of a child till he comes to be a man in his 

 prime. The difference between the diffuse nebulous 

 matter and the star is so striking that the idea of 

 conversion from one to the other would hardly occur 

 to any one without evidence of the intermediate 

 steps. It is highly probable that each successive 

 state is the result of the action of gravity. 



In his last statement, 1818, he admitted that to his 

 telescopes the Milky Way had proved fathomless, 

 but on " either side of this assemblage of stars, pre- 

 sumably in ceaseless motion round their common 

 center of gravity, Herschel discovered a canopy of 

 discrete nebulous masses, such as those from the con- 

 densation of which he supposed the whole stellar 

 universe to be formed." 



In the theory of the evolution of the heavenly bodies, 

 as set forth by Kant, Laplace, and Herschel, it was 

 assumed that the elements that composed the earth 

 are also to be found elsewhere throughout the solar 

 system and the universe. The validity of this assump- 

 tion was finally established by spectrum analysis. But 

 this vindication was in part anticipated, at the begin- 

 ning of the nineteenth century, by the analysis of 

 meteorites. In these were found large quantities of 

 iron, considerable percentages of nickel, as well as 



