8. The heat of the earth's interior. 



a. Hot springs and geysers. 



Experiment 6. A geyser. 



b. Volcanoes. 



(These subjects, The Sun, Stars, and Planets, 

 are continued in the work for the eighth grade.) 



LIGHT. VII. 



9. A brief summary of the facts stated under the same 

 topic in the work for the fifth and sixth grades. 



.0. The bending of light. 



Experiment 7. The path of light through 

 thick glass. 



11. The effect of a prism upon the direction of light. 



Experiment 8. The path of light through 

 a prism. 



12. White light is composed of many colors. 



Experiment 9. Dispersion of light by a 



prism. 

 Experiment 10. The composition of 



white light. 



13. Color. 



a. Depends upon the light reflected. 



Experiment 11. Colors as seen by the 

 sodium flame. 



b. Depends upon light transmitted. 



Experiment 12. The transmission of 



color. 



Experiment 13. Color from reflection 

 and transmission. 



14. The rainbow. 



a. Single. 



b. Double 



Experiment 14. The rainbow. 



