462 



Prof. D. E. Hughes. 



[May 27, 



one-third the power or loudness of that produced by the tone of the 

 musical telephone. We may thus have ten or more telephones of 

 different musical notes, each responding separately in their own tone 

 or all at the same time, as each diaphragm selects its own period 

 from the confused periods of contacts sent by the scraping contact 

 maker. 



In order to verify the results, I have used in these experiments 

 both periodic and mixed sound transmitters, but find that owing to 

 the difficulty of keeping the periodic transmitter and telephone in 

 perfect tune with each other, that the mixed sound transmitter is pre- 

 ferable, as it gives no trouble whatever, and we have more accurate 

 results, as we then have only to keep our telephones in accord with 

 the number of vibrations desired. 



The experiments mentioned in this paper were all made with a fixed 

 note of vibration of the diaphragm of 512 double vibrations per 

 second. I will, however, mention a few made with varying rates of 

 vibration, and as I propose in a future paper to give a more extended 

 series of observations through a wider range : I will confine myself 

 to these examples. 



Fig. 2. 



The diagram shows the results obtained on iron wires of different 

 diameters ; their stable and variable resistance were all reduced to 

 comparative values, the stable resistance being taken as 100. Three 

 telephones were employed, the first having the musical note of G or 



