234 NATURE STUDY. 



recognize it, is to relate it to its natural environment, 

 to describe the places where and the conditions in 

 which it is found, and, if possible, show how it is 

 affected by its environment; how it crumbles or disin- 

 tegrates and forms soil under the action of rain, air, 

 roots ; how it is worn away and carried along and de- 

 posited by waves and streams. If it is possible to study 

 this reaction between the stone and its environment, 

 which corresponds to habit in living nature, it will. make 

 much more intelligible the next step, the life history 

 or story of the formation of the limestone. When the 

 children see that the solid rock breaks down into mud, 

 they will be better prepared to understand that it was 

 formed from mud and animal remains. The story of 

 the animals and other agencies which formed it, and 

 of the process of formation, is largely recorded in its 

 structure, and thus leads to and prepares for the study 

 of the structure of limestone, its fossils and layers, and 

 perhaps of its uses and adaptation to uses. From this 

 we can pass to comparison with other limestone, per- 

 haps with other lime rocks previously studied. The last 

 step is the application, such as the relation of what has 

 been studied to geography, the uses of limestone, and 

 of materials made from it, and the processes of manu- 

 facturing lime. 



A similar line of thought can be followed in the 

 study of sandstone and shale and granite, and of such 

 minerals as coal, the iron ores, quartz, graphite, and 

 pyrite. 



In studying physics and chemistry this order is not 



