PHYSICAL GEOGRAPHY IN THE UNIVERSITY. 67 



not by the simple eyesight of such observers as are found among 

 average college students. But during the same week that the 

 class was examining these tidal tracings in the laboratory, and 

 thereby gaining an approach to a simple inductive knowledge of 

 the principal facts of the subject, the problem was taken up from 

 the other side in I'ectures, which discussed the theoretical conse- 

 quences of the interaction of two bodies, and deduced from the 

 theory of gravitation a number of special results that ought to 

 occur if the theory of the tides is correct. As an aid in this 

 deductive discussion, I placed three great circles of paper around 

 a globe, so as to represent the theoretical arrangement of the 

 tidal equator, and high tide circle and the low tide circle, and 

 their relations to the latitude circles of the earth. Now, return- 

 ing to the tidal diagrams with the results of the tidal theory in 

 mind, it is only the poorly trained, the dull, or the stolid "stu- 

 dent" who feels no mental satisfaction in the successful meeting 

 of the facts of observation and the consequences of theory. 

 Facts before noted, but not understood, now gain meaning; facts 

 before disconnected now fall into their natural relationships ; 

 facts before unnoticed are now searched for and found, and won- 

 der is even excited that they were not seen sooner. Neither 

 induction nor deduction alone satisfies the mind. However full 

 the series of facts, however extended the deductions from the- 

 ory, both facts and deductions are of small value while the}- 

 remain unmated. Properly confronted, they pair off and each 

 one reacts on its mate most favorably. If the facts are well 

 observed and recorded, if the theory is justly based and logically 

 extended to its consequences, the inductions and deductions 

 mutually complete each other, and the mind is satisfied. The 

 window light then seems a dull illumination of the tidal tracings 

 compared to the light that shines on them from the under- 

 standing. 



As with the tides of the ocean, so with the forms of the land. 

 They are but half seen if examined only by daylight. They are 

 less than half appreciated if seen without an understanding of 



