﻿Air Sfc.for Pure Notes of (liferent Pitch. 263 



Pressure p = B . Q . g, 

 p =B .Q .<7, 

 = 0-760 x 13-596 x 9-810 metre. 



If ki 1)0 the unknown, then 



7 ku 



h 



By substituting 



h «l-3968* « =0-003665, 



u =2-600, < = 17°C., 



r =330*88 metre, B = 0*750 metre, 



v =2 x 1023*25 x 0-1095 metre, S = 0*38528 metre, 



we get as ratio of the specific heats of ethyl-ether 



£=1-0208. 



Jaeger* found 1*097 (at 20°) and Mullerf 1-0288 (between 

 45°'4and 22°*5). 



A phenomenon, similar to the one observed in a mixture of 

 air and vapour, I found also in a mixture of air and carbonic 

 acid. 



In the manner already described I filled the tube half full 

 with carbonic acid, then turned the gas off and let the water 

 sink. The upper portion of the tube was thus filled with air 

 and the lower with carbonic acid. With fork c ni and tube II. 

 I found the following readings : — 



Surface of the water below. 



165 1651 . 



165 165 j am 



150 140 



135 135 



130 130) , . ., 



-.oq -.orv > carbonic acid. 



Surface of the water above. 



In both columns the two first half wave-lengths agree with 

 those previously found for pure air, the two last with those for 

 pure carbonic acid. This is a simple method of ascertaining 

 with fair exactness the relative velocities of sound in air and 

 carbonic acid or other suitablo £ases. 



* Wied. Ann. xxxvi. p. 200 (1880). 

 t Wied. Ann. xviii. p. 116 (18tf3). 



