APPENDIX. 



267 



Note D. 



Table VIII, contains a set of experiments with Fig. 10. The tube 

 ABCD was fixed with respect to TVR in such a manner that R was 

 protruded into the tube at distances expressed in the first column. The 

 piston was then moved till the flattening took place, and the note jumped 

 back to the original one, or rather as before-mentioned to one a little sharper. 

 The distance of the piston from the end of the tube, when this took place 

 is seen in the second column. The note to which the pitch had sunk in 

 the third column, and the sharp note to which it returned in the fourth. 



Table VIII. 



PITCH OF REED, 4.87- 



Here the flattening is almost insensible at the mouth of the tube, and 

 when .B»S'= about 14, and is greatest midway. As the first leap takes place 

 when BP=QM, and the second when ^P= 20.78, we may infer the wave 

 of the reed to be 13.4, nearly,* so that here the least effect is produced, 

 when the pipe is nothing or the whole wave, and the greatest when it 

 equals the half wave, as I had stated. The value of BP is very nearly 

 constant, and its variations appear to follow a regular law, its mean value 

 being nearly at the half waves. 



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