X PREFACE. 



have included 1. The history of the art of scientific dis- 

 covery, including all the various discoveries, chronologically 

 arranged. 1 2. The various principles of science upon which 

 the art is based. 2 3. The practical rules and methods in 

 general use. 4. The special details of the modes of research 

 in particular sciences. But, in the first place, the history 

 of the subject has already been given by very able writers ; 

 in the second, I have been obliged to limit myself to 

 qualitative discovery, because the method of such discovery 

 is the basis of all quantitative and further research ; and, 

 in the third, to include only discovery in the sciences of 

 Physics and Chemistry, because those sciences afford the 

 most simple examples of experimental investigation, and 

 may be accepted as simple types of the more complex 

 and concrete ones. The treatise, therefore, embraces but 

 a small portion of a great subject ; it consists simply of a 

 series of chapters, all of them written more or less with 

 the practical view of aiding students in pursuing original 

 scientific inquiry. For the history and philosophy of the 

 subject I must refer the reader to the several books already 

 named ; and for special technical details of working he 

 must consult books on the several sciences. 



1 Consult Baden Powell's Historical View of the Progress of tlie 

 Sciences-, Whe well's History of the Inductive Sciences; Draper's In- 

 tellectual Development of Europe ; Thomson's Histories of Chemistry 

 and of the Koyal Society; Buckley's Short History of the Natural 

 Sciences ; &c. 



2 Consult Whewell's Philosophy of the Inductive Sciences ; Her- 

 schel's Discourse on Natural Philosophy ; Jevons's Principles of Science ; 

 Thomson's Laws of Thought ; Bain On the Senses and the Intellect ; 

 and the various works on logic and the different sciences, 



