Dr. R. Konig on Manometric Flames. 109 



the following mode of giving the desired pitch to the resonators 

 in question. 



Tune a string of the sonometer to the fundamental tone of the 

 sound, and produce on it the harmonic notes one after another. 

 Then place the proper resonator in communication with the ear 

 instead of with the manometric capsule; and while the india- 

 rubber tube is in the ear, it becomes very easy to determine their 

 arrangement and the position for the strongest resonance. 



After having tuned eight of these resonators to c and its over- 

 tones, I repeated the same experiments with this apparatus as T 

 tried on the spherical-resonator apparatus, and obtained exactly 

 the same results. There was not the least sign of any weakened 

 sensitiveness in the flames ; so that this apparatus appears to me 

 exactly fitted for more exact and searching experiments on sounds 

 in general, and particularly those of the human voice, at least 



those composed of notes which do extend beyond c. It is to be 

 remarked that direct employment of the resonators with the ear 

 does not succeed far beyond this limit. 



Unfortunately I am now conviuced that the state of my voice 

 does not permit me to investigate any further in this direction, 

 as I had intended ; so I must be content to show the capabilities 

 of the apparatus, as I shall again, when describing the method of 

 experimenting on the vowel-sounds, and others also, by the eli- 

 mination of single accessory notes, or whole series of them. 



Interference-phenomena. 



In my description of the results obtained by the combination 

 of the notes of two organ-pipes I have not mentioned unison. 

 The combination of two notes in unison has a special interest, 

 on account of the communication of the vibrations and the in- 

 terference-phenomena which may be observed therein. I there- 

 fore preferred deferring their description until now, when I could 

 explain them in connexion with other similar experiments. 



If we place two organ-pipes tuned in unison in communication 

 with two flames and sound only one of them, the flame of the other 

 shows that its air-column also vibrates in sympathy through com- 

 munication; and this passing on of the vibrations takes place even 

 if the organ-pipes are not in exact unison with each other, and 

 therefore when sounded together cause beats to be heard. But it 

 is to be remarked that in this case the sympathetic pipe does not 

 form its own vibrations, but only vibrations which are exactly in 

 unison with those of the one acting on it, so that beats are neither 

 heard nor their effects seen in the flame. If, however, we blow the 

 second organ-pipe and thus cause its own vibrations, they unite 

 with the resonance-vibrations, and the flame shows clearly, by 



