﻿256 Dr. J. W. Low on the Velocity of Sound in 



Considering that any error in the observed value of v 

 becomes greatly magnified in the above numbers, the small 

 deviations from a constant mean are almost negligible. The 

 generally excellent agreement between theory and experi- 

 ment, when a = 330*58 metre, speaks for the correctness of 

 this number as the true value of the velocity of sound. 



If with this value we calculate the constant y for the dif- 

 ferent tubes, we find the following results : — 



Tube. 



c r 



e t . 



9r 



c u . 



c ur 



I 



0-007902 



0-008265 



0008500 



0007642 



0009122 



II 



7830 



8262 



8264 



8046 



8149 



Ill 



8002 



8418 



8543 



7916 



8480 



Mean =0-007989. 



This experimental mean 0*007989 tallies very closely w T ith 

 0'00742, the theoretical value, calculated by means of 

 Kirchhoff's formula* from O. E. Meyer's f constant of 

 friction of air and Maxwell's theory of the conduction of 

 heat. 



We may also calculate k, the ratio of the specific heats, by 

 the formula 



•v^ 



where B = 0*760 metre, Q= 13*596, # = 9*81 metre, and 

 A 1 



Ao ~773* _ 



By substituting these values and putting a = 330*582 metre 

 we find 



k= 1-3947, 



while all previous values lie between 1*419 and 1*3845. 

 y=^+(f--)^ 



where 



« = the true value of the velocity of sound in air, 

 6 = Newton's „ „ „ 



/z = a constant for conduction of heat, 

 v=a constant for friction. 



Vide Kirchhoff's Ges. Abh. p. 543. 

 t Pogg. Ann. xxxii. p. 642. 



