410 THE WORLD MACHINE 



densed objects which would one day result in suns and systems. 

 There was a vein of the poet in his nature ; he must, too, have 

 been a lover of flowers, for this is the analogy which comes 

 to his mind. To such as imagine that scientific papers are 

 always arid productions, unrelieved by the touch of fancy, 

 a paragraph from his paper may be of interest : 



" This method of viewing the heavens seems to throw them 

 into a new kind of light. They are now seen to resemble a 

 luxuriant garden, which contains the greatest variety of produc- 

 tions, in different flourishing beds ; and one advantage we may 

 at least reap from it is, that we can, as it were, extend the 

 range of our experience to an immense duration. For, to con- 

 tinue the simile I have borrowed from the vegetable kingdom, 

 is it not almost the same thing, whether we live successively 

 to witness the germination, blooming, foliage, fecundity, fading, 

 withering, and corruption of a plant, or whether a vast number 

 of specimens, selected from every stage through which the 

 plant passes in the course of its existence, be brought at once 

 to our view ? " 



Herschel had reached this view in the years from 1789 to 

 1791. It was in the latter year that Kant's tract upon the 

 nebular theory was reprinted as a tailpiece to a German 

 edition of Herschel's Structure of the Heavens. The one was 

 at the time the most celebrated observing astronomer, the 

 other the most widely read philosopher, in Europe. The 

 book could hardly have failed to attract widespread attention, 

 particularly from the astronomers themselves. 



It was five years after this that Laplace produced his popu- 

 lar Exposition du Systeme du Monde. At the close of this 

 work Laplace devotes three or four pages to a criticism of 

 Buffon's cometary-impact theory of planetary origins, then 

 adds a brief three paragraphs sketching a theory which he 

 presents as his own. That Laplace had read Herschel is evident 

 from his own pages ; whether he had read Kant is not so clear. 

 He mentions neither the one nor the other. It may be noted 

 that in this same section of his work he had borrowed from 

 Bailly's Histoire an extended argument as to the probable 

 agreement of ancient measures of the earth ; he gave it with 

 an air of novelty, but without a line or a word of credit. 



The theory of Laplace differed in some essential ways from 



