THE STORY OF NINETEENTH-CENTURY SCIENCE 



that the primitive mass of cosmic matter which was 

 destined to form our solar system was revolving on its 

 axis even at a time when it was still nebular in charac- 

 ter, and filled all space to a distance far beyond the 

 present limits of the system. As this vaporous mass 

 contracted through loss of heat, it revolved more and 

 more swiftly, and from time to time, through balance 

 of forces at its periphery, rings of its substance were 

 whirled off and left revolving there, to subsequently 

 become condensed into planets, and in their turn whirl 

 off minor rings that became moons. The main body of 

 the original mass remains in the present as the still con- 

 tracting and rotating body which we call the sun. 



The nebular hypothesis thus given detailed comple- 

 tion by Laplace is a worthy complement of the grand 

 cosmologic scheme of Herschel. Whether true or false, 

 the two conceptions stand. as the final contributions of 

 the eighteenth century to the history of man's ceaseless 

 efforts to solve the mysteries of cosmic origin and cosmic 

 structure. The world listens eagerly and without preju- 

 dice to the new doctrines; and that attitude tells of a 

 marvellous intellectual growth of our race. Mark the 

 transition. In the year 1600, Bruno was burned at the 

 stake for teaching that our earth is not the centre of the 

 universe. In 1700, Newton was pronounced "impious 

 and heretical" by a large school of philosophers for 

 declaring that the force which holds the planets in their 

 orbits is universal gravitation. In 1800, Laplace and 

 Herschel are honored for teaching that . gravitation 

 built up the system which it still controls ; that our 

 universe is but a minor nebula, our sun but a minor star, 

 our earth a mere atom of matter, our race only one of 

 myriad races peopling an infinity of worlds. Doctrines 



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