182 



INTRODUCTION TO GENERAL SCIENCE 



References : 



1. 1205:13. 



2. 1205:13-15. 



3. 1304:13-14. 



4. 1304:44-45. 



5. 1601:15-18. 



6. 1601 : 18-21. 



a. 1201:119-121. 



6. 1202 : 177-180. 



c. 1203:14-17. 



d. 1206:112-114. 



e. 1208:30-40. 

 /. 1209 : 18-28. 

 g. 1302:57. 



h. 1310:40-44. 



i. 1311 : 131-132. 



j. 1312 : 262. 



k. 1604:18-28. 



I. 1612:7-16. 



Oxidation. 



Effects of Heat and Cold. 



The Atmosphere in Relation to Decay. 



Agents of Erosion. 



Water and its Work. 



Living Forms and their Work. 



Work of Oxygen. 



Action of Freezing Water and Ice. 



The Causes of Decay in Rocks. 



The Effect of Heat and Cold. 



Igneous Agencies. 



Agents of Weathering. 



Weathering by Oxygen. 



Freezing and Thawing. 



The Glacier's Work, 



Disintegration of Rock through Heat. 



Effects of Weather upon the Land. 



Soil Makers. 



129. EROSION 



Erosion is, as has been stated, the most rapid factor in 

 weathering, but it would not be so active if it were not for the 

 work of the other factors. The work of running water, how- 

 ever, is very great. Deep valleys and canons have been 

 dug by moderate-sized streams, working during countless 

 centuries; in other valleys lakes have been formed by some 

 stoppage at the mouth of the river. The result of the water's 

 work has been to carve our hills into their present state, for a 

 large number of our mountains were really huge billows in the 

 surface of the earth, until water cut some places deeper than 

 others and gave us the rugged, cragged mountains. 



