THK SKNsK < > I ' HKAKINtt 



220 



at three pniuls of its periphery .1, />, C. The opening .1 serves, as in 

 llelmholt/.' re>oii;ili.rs. In receive \\\<- sound - waves ; the lumen of lliis 

 ajirri urc, unlike Helmholtz' resonators, can In- altered ;il \\ill by means of 

 diaphragms ,/, e) \\hich can lie screwed io the end of the tube A, F. On 

 varying the lumen of this diaphragm, i he proper tone of the resonator alters, 

 and Kdelmann provides diaphragms of dill'erenl apertures, l>y which the 

 proper tone of the resonator can lie varied exactly from semitone to semitone. 



Kx.. '.a. Si-iir> ul' Yi'simators ; Edi-linann's new model. 



The semitones which can be analysed by these resonators are 72, and form 

 the 6 octaves from C of the contra-octave to c of the 4 times accented octave 

 (from 32-33 to 2068'6 d.v.). 



The opening G serves for hearing, while the opening B, which is absent in 



|'K.. '.'0. Section 



<>n<- ul' lvl''lni.-mu's ivsonatni-s. 



Ilelmholt/.' r:.-onators, is made air-t ight l>y a thin, circular plate of resonat- 

 ing wood, and conducts the sound-waves from an instrument placed direct ly 

 against it to the air contained inside the j-e-onator. This is particularly 

 advantageou- in the analysis of feeble tones, which cannot be analysed 

 with Helmholtz' resonators because their waves are weakened by transmis- 

 sion through the air. 



Even without the aid of hearing, the compound nature of 

 tones can IK- demonstrated physically by the Konig's name 

 manometer (Vol. III. p. 131). 



