PAPERS OX CHEMISTRY AND PHYSICS 115 



THE VARIATION OF PITCH OF THE NEW 

 SINGING TUBE WITH LENGTH 



Chas. T. Kxipp axd A. J. McMastee, Uxiyersity of 



Illixois 



That the pitch of the new singing tube depends upon 

 several factors, including the difference of temperature 

 between the closed end and the remainder of the tube, 

 the absolute temperature, and the linear dimensions of 

 the tube has been known for several years. The rela- 

 tion between absolute temperature and pitch has been 

 investigated, 1 and so also has the relation between pitch 

 and density- ; however, an exact and quantitative mathe- 

 matical statement of the relations involved in the pro- 

 duction of sound by heat by means of the new singing 

 tube has not been offered. The object of the present 

 investigation was to indicate in an experimental manner 

 the variation of pitch with the external length of the 

 tube. 



With this aim in view, a tube was constructed of pyres 

 glass, of the form shown in Fig. 1. The dimensions of 

 both the inner and outer tubes are given in Table I. 



TABLE I 



Tube Xo. 1. 



Inner tube: length = 65.0 mm 



inside diameter = 7.0 mm 



wall thickness = 0.75 mm 



Outer tuba: inside diameter = 10.6 mm 



wall thickness = 1.0 mm 



The tube was then water-jacketed over its entire 

 length to within 2 cm of the closed end, which was heated 

 by means of a ring burner. The pitch of the tone emitted 

 by the tube was measured by comparison with a tone 

 variator. The tube was then removed from the jacket, 

 and a portion of it (2 to 5 cm) cut ofr at the open end. 

 The water jacket was shortened and replaced and the 

 pitch again measured as before. This procedure was re- 

 peated until the outer tube was but a little longer than 



1 Phys. Rev.. X. S.. Vol. XV. p. 336. 

 ' Phys. Rev.. X. 5.. Vol. XXIII. p. 115. 



