operational uses, was yet of great importance., The quantity 

 of information obtainable on underwater sound transmission," 

 background noise, reverberation and other factors, made it 

 possible, by the end of the war, to predict at least approx- 

 imately the performance of a particular piece of equipment 

 before it had even been built „ The Sonar Analysis Group in 

 New York, for example, computed the expected performance of 

 standard types of listening gear and also considered the spe- 

 cial advantages to be gained from using listening gear oper- 

 ating at low available frequencies,, 



35 



