INTROD UCTION 1 3 



delicate relations. It is upon these facts that a true system of 

 gradation in nature-study and science must rest. The attempt is 

 usually made to establish grades by changing from one branch of 

 the science to another and by the introduction of new and often 

 unrelated subject-matter. This is done partially on the theory that 

 repetition of the same thing becomes tiresome, which is true, and 

 partially on the theory that, to keep alive the interest, the subject 

 must be changed, which is not true. Nothing could be more detri- 

 mental to the genuine development of the pupil than the continual 

 snapping of his thread of interest which is involved in the customary 

 plans of gradation. The materials and phenomena of nature as 

 subject-matter for study do not in themselves actually change ; 

 the continual and growing interest in the same thing, therefore, 

 must always be preserved. 



Nor is the distinction between nature-study and science, some- 

 times made, that the results in the latter may be more quantitative 

 than in the former, a valid one. Such results in nature-study are 

 possible and proper in any particular field when the student of science 

 would find them desirable, and necessary. For example, in all study 

 of physical force there is but one line open to the student who 

 attempts to investigate, whether he is six years old or sixty, and that 

 is to find out its value ; this can be done only by measuring it. 



The pupil very soon exhausts the qualitative aspects of such a 

 subject, if indeed he has not already done so before he enters school. 

 By this it is not meant that the pupil from the beginning must be 

 asked to run down the result to the last decimal point in an 

 indefinite series. In the outset it may involve none of the usual 

 units at all. He may get the result in terms of which he can himself 

 lift or push or pull, or otherwise physically accomplish. It is only 

 then that he actually finds the need of the unit, pound, foot, gallon, 

 etc. ; it is as these gradually become definite in his mind that the 

 fractional part has any value to him. 



Where the average student of science might be able to develop 

 the picture he seeks by the analysis of a single leaf, or of a drop of 

 water, or of an ounce of earth, the beginner in nature-study must 

 use bushels, gallons, or pounds. There are two reasons for this : 

 first, the pupil's undeveloped imagination must picture in the large 

 — he cannot think in grains of sand ; and second, because, unskilled 

 in manipulation, the liability to losses during experimentation with 



