LIMITS OF AUDIBLE SOUND. 61 



of a bassoon. It is not a new instrument, but it is on a new scale 

 This, as I hope to demonstrate afterwards, brings out the CCC, the 

 lowest note of the 16 feet octave, with a tone which you people may call 

 musical or not, but I think it is. At any rate it is not wanting in 

 power or in intensity. I have intentionally omitted to speak of one 

 excellent set of investigations on the upper limit of musical sound, 

 because Mr. Galton, the author, is here present himself, and will 

 explain them. 



The CHAIRMAN : I have to ask you to again express your thanks 

 to Dr. Stone for these few supplementary remarks ; but I think before 

 we have any discussion on these communications, we had better 

 complete this branch of the subject, and I will therefore call on 

 Mr. F. Galton, F.R.S. 



Mr. GALTON : I thought it would be of convenience to experi- 

 menters, that I should exhibit some little instruments I have combined 

 for ascertaining what the upper limits of audible sound may be in 

 different persons of the same race, and in individuals of different 

 races, and in different kinds of animals. It is, of course, a matter of 

 great interest to know whether insects and such small creatures can 

 hear sounds, and can in any sense of the word, converse in language 

 which to our ears is utterly inaudible. When I first devised to 

 make experiments, I was checked by the great difficulty of finding 

 instruments that vibrated with sufficient rapidity for the purpose in 

 question. Dr. Wollaston (to whom we are indebted for the first 

 experiments ever made on this subject, and for the fact that vibra- 

 tions exist which the ear is incompetent to seize and render into- 

 sound) found very great difficulty in making his small pipes. I tried 

 several plans for obtaining acute notes, and the one I finally adopted 

 was this : I made a very small whistle, whose internal diameter was 

 much less than one-tenth of an inch I have many such here, made 

 for me by Massrs. Tisley and Spiller, Opticians, 172, Brompton-road, 

 with a plug at the bottom, which plug is screwed up by a graduated 

 screw. The graduations are marked on the side, so that when you 

 use the instrument you know the depth of the tube, and knowing 

 what that is, it is a matter of calculation to learn the rate of vibration. 

 There is, however, a good deal of uncertainty in the matter, because 

 there must be some fair proportion between the length and width of 



