194 THE BEASON WHY. 



1 My son, give, I pray thee, glory to the Lord God of Israel, and make confession 

 unto him." JOSHUA vii. 



850. Why are feathers usually fastened to the ends of 

 arrows ? 



Because the greater friction of air acting upon them, opposes the 

 progress of that part of the arrow in a greater degree than it does 

 the other portion. The effect is, to keep the point of the arrow 

 forward, and in a straight line with its opposite extremity. If the 

 arrow were shot the reverse way from the bow, it would turn 

 round, in the course of its flight, in consequence of the friction of 

 the air, offering greater resistance to the progress of the feathered 

 end. 



Fig. 38. BOW AND AEKOW. Fig. 39 JEW'S HABP. 



851. Why does a Jew's harp give musical sounds ? 

 Because the vibrations of the metal tongue are communicated to 



the ear. 



852. Why will not the Jew's harp produce loud sounds 

 unless it is applied to the mouth ? 



Because the vibrations are not very intense, but when it is blown 

 upon by the breath, the air is pressed upon it, and the vibrations 

 are thereby rendered more powerful. 



853. Why does the alteration of the arrangement of the 

 mouth, affect the formation of the sounds ? 



Because it sends the air to the tongue of the harp in a greater or 

 letter degree of compression. 



