216 



The Hon. J. W. Strutt's Remarks. 



All the columns except the last are copied from Dr. Sond- 

 hauss' s paper. It will be found that the observations are better 

 represented by (VII.) than by (A) ; but it must be remembered 

 that (VII.) contains an arbitrary constant, c, which acts uearly as 

 a constant multiplier, although, if I understand Dr. Sondhauss 

 aright, its value was not determined from this series of experi- 

 ments. However this may be, it is certain that nearly all the 

 values of n calculated from (A) are too great. The fact is that 

 (A) is scarcely applicable to the experiments at all. In only five 

 cases is the ratio of the diameter of the neck to the dimension of 

 the vessel even tolerably small. These are 1, 4, 11, 12, 14; 

 but in 1, on account of the extremely small diameter of the neck 

 and its considerable length, the influence of friction is probably 

 sensible ; and its effect would be to lower the pitch. The body 

 in 4 is cylindrical, and perhaps too long in proportion to the 

 quarter wave-length. In 11, 12, and 14 the agreement is suffi- 

 ciently good. I consider accordingly that there is no evidence 

 in the Table unfavourable to formula (A), supposed to be stated 

 with the proper restrictions. In my own experiments, made by 

 the method of resonance, I found a very good agreement between 

 the directly observed and the calculated pitch, the average error 

 being under a quarter of a semitone. Even with formula (VII.) 

 as the basis of calculation there would be a fair agreement, cer- 

 tainly better than is the case with Dr. Sondhauss's own experi- 

 ments. The difference between (VII.) and (A) is, as I have 

 already remarked, comparatively small, and could only be cer- 

 tainly distinguished under favourable circumstances. Not find- 

 ing the necessary data in Dr. Sondhauss' s paper, I venture to 

 quote some experiments from the paper on Resonance. There 

 are seven observations in which the necks were sufficiently long 

 to bring out the difference between the formulae, being more than 

 four times the diameter. It will be seen that the alteration is in 

 every case for the worse if the formula (VII.) is substituted for (A). 



n, observed. 



n, calculated 

 from (A). 



n, calculated 



approx. from 



(VII.). 



126 



1087 



180 



228 



204 



182 



384 



127 7 



1077 

 1797 

 2337 

 201-9 

 186-3 

 391-6 



131 

 110 

 184 



239 

 207 

 190 

 400 



These experiments seem to decide the question ; but it would 

 be interesting to see if Dr. Sondhauss obtained a similar result 



