[ an ] 



XXV. Remarks on a Paper by Dr. Sondhauss. 

 By the Hon. J. W. Strutt, Fellow of Trinity College, Cambridge*. 



IN Nos. 5 and 6 of PoggendorfTs Annalen for this year 

 there is a paper by Dr. Sondhauss "On the Tones of 

 Heated Tubes and Aerial Vibrations in Pipes of various forms/' 

 in which are given formulae of considerable generality embodying 

 the results of original and other experiments. Many years agof 

 Dr. Sondhauss had investigated the influence of the size and form 

 of flask- or bottle-shaped vessels on the pitch of the sounds pro- 

 duced when a stream of air is blown across their mouth, and had 

 obtained as an empirical formula for flasks with rather long cy- 

 lindrical necks, / — 



n =Wk' w 



where n is the number of vibrations per second, a the area of 

 the section of the neck whose length is L, and S the volume of 

 the body of the flask. C is a constant determined by the expe- 

 riments. On the other hand, when L is very small compared 

 with the diameter of the neck, which then becomes a mere hole, 



n=C^ (II.) 



S 2 



In the paper now under discussion it is sought to fill up the 

 gap, as it were, and the following formula is arrived at as appli- 

 cable for all proportions of L and &*, 



n=- / *" 



or, as I prefer to write it, 



(VII.) 



V v ( s+ i^ (W(r; 



in which a= velocity of sound, c is a constant, of which Dr. 

 Sondhauss says that it relates to the change in the velocity of 

 sound in closed spaces from which the sound-waves have only a 

 restricted exit; and its value, as found from the experiments, is 

 approximately 2*3247 . 

 In (VII.), if <t be small, 



w=-Va/_£- (VIII.) 



4^/cV LS V J 



If, on the contrary, L be very small, 



n=~^ (IX.) 



* Communicated by the Author, 

 t Pogg. Ann. vol. Ixxxi. 



