506 



BELL SYSTEM TECHNICAL JOURNAL 



Montlilv Average of Diurnal Variation of Noise 



Green I larhor, Mass. 24,000 Cycles 



Sept., 1923— Jan., 1924 



TTtTT 



I 



mr 



M 



inlt 

 I'j! 



IIJH 



Monthly Average of Diurnal Variation of Noise 

 Crt-vn Harbor, Mass. 34,000 Cycles 



1923 



