THE SCIENCE OF HAPPINESS 



poetry to prose, and made himself instant master in the 

 new field. Adam Smith, professor of Moral Philosophy, 

 resigned his university chair and turned his attention to 

 economic questions, and, after ten years of study, pro- 

 duced, at fifty-three, under title of The Wealth o) Nations, 

 the work that founded the modern science of Political 

 Economy. The economic system which Smith's work 

 supplemented and perfected had its chief exposition in 

 the Tableau economique which Fran9ois Quesnay, 

 the French professor of surgery and personal physician 

 to Louis XV., published at the age of sixty-two, and to 

 the same author's La physiocratie, ou constitution 

 naturetle du gouvernement le plus avantageux aux 

 peuples, which appeared nine years later. Similarly 

 J. J. Rousseau's Contrat social, "the bible of modern 

 democracy," was a work of mature manhood, ap- 

 pearing when its author was in his fiftieth year. 



Faraday was past middle life before he turned his at- 

 tention to electricity, yet his experiments in this field 

 laid the foundation of the modern science of electro- 

 dynamics. S. F. B. Morse, the artist, was thirty- 

 six before he first became interested in electricity. 

 He was forty-one before he conceived the practicability 

 of the electrical telegraph, and past fifty before he 

 demonstrated the validity of his idea. James Watt 

 also was past fifty before he demonstrated the com- 

 mercial value of his improved steam engine. Fulton 

 was past forty before his first steam boat crept along 

 the Hudson, and Stephenson was almost fifty when the 

 "Rocket" made him famous; but both these inventors 

 had virtually perfected their mechanisms at earlier 



