ABSOLUTE CALIBRATION OF CONDENSER TRANSMITTERS 115 



found to have a maximum value of nearly Z.Z at w/2n = 3500 c.p.s. 

 This means that the air resonance adds a factor of 1.65 to the ordinary 

 doubling of pressure caused by a plane wall. A substantially similar 

 calculation has been given by W. West.^' 



The observed RfIRp is a maximum at 3,500 c.p.s. but its value is 

 somewhat larger — nearly 3.65. 



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