442 



GENERAL SCIENCE 



FIG. 340. Violin. How are high and 

 low tones produced on the violin? 



FIG. 341. Why is it necessary to 

 change the position of the left hand? 



FIG. 342. Xylophone. Why are the 

 pieces of metal of different size? 



FIG. 343. 



21. Why should you never leave the telephone receiver off the 

 hook? 



22. Why is it unfair and discourteous to use the telephone for a 

 long time talking about unimportant things? 



23. Who is usually more courteous over the telephone, you or 

 " central "? 



24. What parts of this chapter do you find useful to you? 



