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PHILOSOPHICAL TRANSACTIONS 
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OF THE 
ROYAL SOCIETY OE LONDON. 
Series A, Vol. 221. Pp. 389-430. 
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A SELECTIVE HOT-WIRE MICROPHONE. 
BY 
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W. S. TUCKER, D.Sc., A.R.C.Sc., 
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AND 
E. T. PARIS, M.Sc. (Lond.). 
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Printed and Published for the ROYAL SOCIETY by 
HARRISON AND SONS, Ltd., 44-47, ST. MARTIN’S LANE, LONDON, W.C. 2. 
printers in ©rtrinarg to f&iS iflajetftp. 
1921. 
Price Four Shillings and Sixpence, 
A 592. 
3.3.21 
