In the specification of the patent applied for on the list of July 1877 he showed a sketch of an instrument which consisted of a diaphragm, with a small platinum patch in the centre for an electrode, against which a hard point, made of plumbago powder cemented together with india-rubber and vulcaniz
plumbago הגייה עם משמעויות, מילים נרדפות, הפכים, תרגומים, משפטים ועוד