Objective Reality of Combination Tones. 

 Instrument. Interference Resonator. 



355 



Instrument. Mirror Resonator. 

 Summation-Tones. 



Number of 

 holes in siren. 



Interval. 



Frequencies. 



Sum. 



15 and 12 



16 „ 12 

 16 „ 9 



Major third. 

 Fourth. 

 Major sixth. 



320 256 

 329'15 246-85 

 360 216 



576 

 576 

 576 



Negative Results. 



We have tried several times to obtain indications of com- 

 bination-tones when the primary notes were produced by 

 tuning-forks. Two of Konig's large forks adjusted to 48 

 and 112 vibrations produced no effect when bowed simulta- 

 neously before the collector , and, as has been stated, smaller 

 forks giving 256 and 320 vibrations have been placed inside 

 the collector when sounding loudly. No effect whatever was 

 produced, and there can be no doubt that if objective com- 

 bination-tones are produced in such cases they are very much 

 less intense than those generated by the siren. 



Experiments have been made with reeds and with organ- 

 pipes, but up to the present with uncertain results in the first 

 case and negative results in the second. We hope to inves- 

 tigate these cases further. 



