METHOD OF STUDYING MATERIAL. 215 



following rules, which will greatly help us in unifying 

 our ideas of form or structure, and in gaining and con- 

 veying to others good mental pictures of form; As 

 minerals are distinguished by their mineralogical and 

 chemical properties rather than by their forms, these 

 rules have little application in the study of minerals 

 and rocks. 



First. Study and describe the whole before taking 

 up its divisions, the central or main part before con- 

 sidering appendages. 



Second. In studying and describing parts or appen- 

 dages, first relate them to the whole. 



Another rule may be added, not so widely applicable, 

 but helpful in insuring logical order or sequence. It 

 will also prevent a useless waste of material, so common 

 when pupils study without order. Those parts should 

 be studied first which are most easily observed, such 

 as the outer parts of the flower and the bark of a tree 

 trunk, and those left to the last which are enclosed by 

 other parts, and for the study of which other parts 

 must be removed. 



Third. In studying, work from the base upward, and 

 from the outside inward. 



To insist on a rigid compliance with these rules in 

 every case would make our work mechanical. But it is 

 helpful to keep them in mind, particularly in work 

 with older children. 



The order in studying structure, particularly with 

 younger children, will be greatly influenced by the law 

 of apperception, and the law of interest, so closely re- 



