502 BELL SYSTf.M TF.CIIXIC.IL JOL'KXAL 



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MdiithK- A\crage of Diurnal X'ariation of Noise 

 Bi-lfast. Main.- 24,(UII) Cvrli-s 



1924 



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MoiiiIiIn Avir.iKf of Diiirn.il Wiriation of Noise 

 Belfast, Maine 36.000 Cycles 



1924 



