642 



Ahliongl) OMi' only receiver was a small, not verj favourable aerial, 

 we were able re|)eatedlj to talie long telegrams, tlie signals of which 

 came in absolutely clear. 



Fig. 5. 



Record of signals from the alternator on the Malabar at Bandoeng, 



made in Leyden January 13th, 1923. 



To what extent can the reception bj' means of the galvanometer 

 stand conipai'ison with the ordinary telephone reception? 



In order to answer this question we shall first compare the sen- 

 sitiveness of the two instruments. The huuian ear is a very sensitive 

 organ. According to M.\x Wien ') il is sut'ficient to ap[)ly to the 

 tym|(anic membrane an energy amounting to 0.83 ,-, lO^'^ e,.gg 



') Max Wjen Ueber die Empfindlichkeil dcs nienschlichen Ohres fur Tone ver- 

 schiedener Hohe. Plüger's Arch. f. d. ges. Physiol. Bd. 97, S. 1. 



