VIBRATIONS OF AIR IX TUBES. 



377 



Fig. 227 serves to represent the motion of a stationary wave in 

 die same manner in which fig. 210 represented that of progressive 

 waves. A piece of paper, as described on page 331, is placed with the- 

 >lit along the dotted line, and the book drawn along underneath it. 





mm 



\\\\\\\\ 



LAW. 



1 



Fro/227. 



n tubes open at one end only, the air performs quite 

 imilar vibrations to those in tubes open at both ends. 



V tube closed at one end behaves exactly like one half 



. 

 >f a tube whichjhas twice its length and is open at both 



,:nds ; the closed end of the former corresponds to the 

 niddle of the latter, and the open end corresponds to- 

 1'iie of the open ends of a tube twice as long and open, 

 t both ends ; in other words, at the open end a ventral 

 segment is produced, at the closed end a node is formed.. 

 t is evident from this that a tube closed at one end 

 lives out the same note as that produced by a tube 

 ifhich is twice as long and open at both ends. 



Vibrations in tubes may be produced in various ways;, 

 lost easily by resonance. If a tuning-fork is sounded 

 nd held across the upper end of a tube the air in which' 

 capable of vibrating at the same rate as the tuning- 

 >rk, the note will considerably increase in intensity in 



