Iß MIT. 111. T. TRP.ADA. 



Oldening. Arrangements which in the earlier part of the exjieri- 

 ment had been used for guiding the motion of the pipe and for 

 reading its height were afterward dispensed with. Tlie verticaUty 

 of the pipe was approximately secured hy a straight brass rod 

 fixed parallel along the side of the pipe at a distance of 2,o cm, 

 this rod being held in contact with the side of the tank during 

 tlie raising and lowering of the pipe. 



Holes which had to be covered, were closed air-tight with 

 curved plates of zinc closely fitting the side of the pipe, and 

 sealed with a kind of tallow. The slis-lit irre2;ularitv on the 

 inner wall of the pipe due to the closing of the hole in this 

 way, was found to affect the velocity of sound within the pipe 

 in no sensible degree. 



The results of the experiments are summarized below : 



a) Correction for the open end. 



First, the correction of the length due to the open end only 

 was determined in the usual manner, before any holes were made. 

 The results gave 0.42 R for the mean value, where R is the sec- 

 tional radius of the pipe. 



b) One circular hole. 



In Figs. 4,5 and G, the relation is given between the distance 

 d of the center of the hole from the open end and the total length 

 L, from the open end to the water surface which gives the 

 maximum resonance for different tunins; forks. The difference 

 of the ordinate between the curve and a straight line through 

 the origin making an angle of 45° with the axes, gives the 

 distance / of the center of the hole from the water surface. The 

 value of -.y-^ = (l where -< is the wave-length corresponding to the 

 the note, may be considered as the correction due to the lateral 

 opening. It will be seen that the correction increases first 



