(2) After the investigator has his facts to build upon; and these may be few or many――sometimes even a single fact is sufficient――then may he theorize as to a possible explanation of them. Here is where the real work of the born genius tells. To some the facts are nothing but words, to others they mean universal laws and great inventions. Who but a Newton could have seen the law of gravitation in the falling apple? Who but an Edison could have seen the phonograph in the sound wave and wax? It must be recognized that this remarkable imaginative insight is inborn in some cases; and yet this does not preclude the necessity for _cultivating_ this power, though it may be only in a rudimentary state. Here is another opportunity for the school teacher; namely, to train in every legitimate way the _constructive imagination_. (3) Having once constructed the hypothesis, the honest scientific investigator at once proceeds to subject it to a series of most rigorous tests. It is well to see big things in a little fact; to have a mind as fertile in new ideas as a watered garden――this is genius! But is it not more incumbent to have a conscience so keen, that nothing will be allowed to pass for truth which has not received ample verification? Intellectual dishonesty is quite as common as moral dishonesty. Moreover, one must maintain an _open mind, absolute candor, and a willingness to abandon the most cherished theory_. Often it is much easier to _explain away_ contradictory facts than it is to forsake a _pet theory_. =12. OUTLINE.= THE AUXILIARY ELEMENTS IN INDUCTION――OBSERVATION――EXPERIMENT―― HYPOTHESIS. (1) The Foundation of Inductive Generalizations. (2) Observation. Defined. (3) Experiment. Defined. Compared with Observation. (4) Rules for Logical Observation and Experiment. Their need. First Rule. Second Rule. Third Rule. Fourth Rule. (5) Common Errors of Observation and Experiment. (1) Preconceived Ideas. (2) Confusing the Observed with the Inferred. (3) Ignoring the Exceptions. (4) Sympathy and Undue Interest. (5) Inattention and a Fallible Memory. (6) The Hypothesis. Defined and Illustrated. (7) Induction and Hypothesis Distinguished. (8) Hypothesis and Theory Distinguished. (9) The Requirements of a Permissible Hypothesis. (1) Conceivable, (2) Capable of proof or disproof, (3) Adequate, (4) Simple, (5) Not contradictory. (10) Uses of Hypothesis. (1) A working basis, (2) Guide to ultimate truth, (3) Discoverer of immediate truth, (4) Probable explanation. (11) Characteristics Required by Scientific Investigators. (1) Accurate observer, (2) Constructive imagination, (3) Passion for truth. =13. SUMMARY.=