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PART Y. 



SPECIAL METHODS OF DISCOVERT. 



CHAPTER L. 



SPECIAL EMPIRICAL METHODS OF SCIENTIFIC RESEAKCH. 



As but few investigators have left behind them a record of 

 the exact circumstance or conditions which immediately 

 led to their discoveries, I have been obliged in many cases 

 to infer from such few particulars as have been handed 

 down, and from my own experience as an investigator, 

 what must have been, or probably was, one or more of 

 the conditions which led to those discoveries, and have 

 classified the discoveries accordingly. 



The methods and processes of discovery, although 

 essentially and chiefly mental, are partly physical, and 

 are determined by the laws of nature ; obedience to nature 

 is the prime condition of discovering new truths. No 

 two investigators work exactly alike, but all are prac- 

 tically guided by the same general rules, because the 

 fundamental laws of science and rules of thought are 

 the same for all men. As scientific investigation is not 

 a supernatural process, but is subject to laws, there 

 must exist a system of general rules of qualitative re- 



