Velocity of Sound Waves in Tubes. Pal Lb 
through the tubes measured .48 cm. in advance of the free air wave 
and the tube length shadows were 4.56 em. long. Assuming that the 
entire gain in space traversed occurred while the waves were inside 
the tubes (an assumption which I think is not entirely true) we would 
have a relative increase of velocity within the tubes of .48 = 4.56, or 
10.5 percent. 
Plate I. 
It happens that none of the observations of Table II was made with 
a tube of the same size as the smallest one used by the author. For 
a tube about 40 percent larger Seebeck and Miiller obtained values 
approximately 5 percent less than the free air velocity—depending on 
the pitch of the sound. Thus it would appear that the total difference 
between their and the writer’s results is in the neighborhood of 15 
percent. 
