120 SCIENCE OF COMMON THINGS. 



Best conductors of sound. Musical sounds. "What is a noise ? 



The space between the laths should be filled with 

 shavings or sawdust ; and then no sound would ever 

 pass from one room to another. 



7*54 Why should shavings or sawdust .prevent the. transmission of sound 

 from room to room ? 



Because there would be several different media for 

 the sound to pass through ; and every change of medium 

 diminishes the strength of the sound- waves. 



7*55 What solids are among the best conductors of sound f 



Iron and glass ; sound is transmitted by them at the 

 rate of 17,500 feet, or more than 3 miles in a second ; 

 after these rank copper, several different kinds of wood, 

 silver, tin, &c. 



CIIAPTEK II. 



VOCAL AND MUSICAL SOUNDS. 

 7*50 What is a musical sound? 



A musical sound is produced by regular undulations 

 or vibrations a succession of sounds following each 

 other with perfect uniformity. 



7*57* How does a noise differ from a musical sound f 



A noise is the result of very irregular or disturbed 

 undulations or vibrations. 



7*58 Do all persons hear sounds alike f 



The faculty of hearing depends upon the construc- 

 tion and sensibility of the ear, and as this differs in dif- 

 ferent individuals, it is certain that all persons will not 

 hear sounds alike. 



7*59 What is meant by the terms concord and discord f 



When two tones or notes sounded together produce 

 an agreeable effect on the ear, their combination is 



