• The Inventers Tools of the Trade Quantitative Laboratory  Instrumentation 
  • Sound analyzers the Koinge manometric flame apparatus.
  •  Bell used this type equipment to study the performance of his microphones and in his display at the centenarian exhibition.
  • It was the oscilloscope of the day.

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  • Bell Studied  the electromagnetic effects of undulating currents and the characteristics of his variable resistance microphones using  versions of the manometric flame apparatus such as those displayed below.
  •  He replaced the rubber diaphragm "C"  in figure 651 with an iron disc which was driven by an  electromagnet
  • The modulated flames were viewed  in a rotating mirror.
  •  This apparatus was capable of giving quantitative performance for microphones, and receivers
  • He used them in the spring of 1876 and at the Philadelphia Centenarian Exhibition

Manometric Flame Apparatus in Our Collection

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Copyright 12/06/2004 Jim & Rhoda Morris