PREFACE. 



It is fortunate for a person who publishes a book 

 wanting in its title-page that passport to public 

 favor which lies in a name, that his subject requires 

 no such adventitious aid. 



On certain subjects of an elementary and scientific 

 nature, a writer's name has great weight ; but with 

 a work of this kind, consisting of a mere detail 

 of facts, and a chain of reasoning, and therefore 

 resting upon its own intrinsic merits, a name ought 

 to have no more influence than in a court of justice 

 is allowed to character against clear and positive 

 testimony. Facts are substantiated by evidence, 

 not by opinions ; and reasons are enforced by prin- 

 ciples and comparison. This work aspires to no 



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