and on Reed Organ-Pipes. 



243 



Table I. 



I have found this table as correct a general standard as I 

 could well expect; for vowels, it must be considered, are not 

 definite sounds, like the diiFerent harmonics of a note, but on 

 the contrary glide into each other by almost imperceptible gra- 

 dations, .so that it becomes extremely difficult to find the exact 

 length of pipe belonging to each, confused as we are by the 

 difference of quality between the artificial and natural vowels. 

 Future experiments, in more able hands than mine will, I 

 trust, determine this matter with greater accuracy, and I should 

 not even despair of their eventually furnishing philologists with 

 a correct measure for the shades of difference in the pronunciation 

 of the vowels by different nations. 



A few theoretical considerations will shew that some such 

 effects as we have seen, might perhaps have been expected. Ac- 

 cording to Euler*, if a single pulsation be excited at the bottom 

 of a tube closed at one end, it will travel to the mouth of this 

 tube with the velocity of .sound. Here an echo of the pulsation 



* Prob. 77, and Cors. Schol. to Prop. 76- and Schol. 2 and 3, Prop. 78. in Nov. Comni. 

 Petrop. XVI. Mem. Acad. Berl. 1767. See also Enc. Metrop. Art. Sound, p. 776. 



HU 2 



