NIL 3511. 



Interval Apparatus, Triad Apparatus, Resonators. 



449 



53507. 1:7. 



53508. 1:6. 



A! so with 404, 408, 412, 416, 420, 424, 428, 432, 436, 438, 440, 442, 444, 446, 448, 449 com- 

 pound vibrations. 



As blower for this apparatus the most suitable to use is the blowing table for constant pressure, 

 No. 53,229, or the Whipple Double Blower, No. 53,230, with wind chest and Table No. 53,231. 



53.504. Triad Apparatus, after Prof. Stumpf, Berlin, for demonstrating the major and minor 

 triad at four different positions 



With this apparatus it is possible to demonstrate the major triad (4:5: 6) and the minor triad 

 (10 : 12 : 15) iii four different pitches, and to determine by this means the pitch which forms the most 

 perfect harmony. The chords are based on a frequency of 100. Number of vibrations: (a) 100, 120, 125, 

 l.">0; (b) 200, 240, 250, 300; (c) 400, 480,500, 600; (d) 800, 960, 1000, 1200; as complements for the 

 difference-tones and overtones: (e) 80, 160, 640, 720; (f) 700, 900, 1100. 



53.505. Triad Apparatus of 24 Massive Tuning Forks on Resonance Boxes 



Fequencies: 100, 120, 125, 150; 200, 240, 250, 300; 400, 480, 500, 600'; 800, 960, 1000, 1200; 1600, 

 1920, 2000, 2400; 3200, 3840, 4000, 4800. 



53.506. Acoustic Apparatus after Prof. Ebbinghaus, Figure, comprising Whipple Double 

 Blower No. 53,230, a Wind Chest with Table No. 53,231, and Interval Apparatus and 

 Tonometer after Ebbinghaus No. 53,503, one each Tone Variator after Stern for 

 .150 300 compound vibrations No. 53,482, for 275 550 compound vibrations (by 

 special arrangement), for 400 800 compound vibrations No. 53,485, for 600 1200 vi- 

 brations No. 53,487, and a Eeed Pipe with sound horn and deep tone c_ x = 64 compound 

 vibrations (ut x = 128 v. s.) No. 53,282 



As to the individual apparatus, kindly refer to the text under the List Nos. given. 



53.507. 3 Resonators, Figure, of different shape (spherical, conical, and prismatic), of 



different material (glass, pasteboard, wood) and of different pitch (g 1( e 1 

 ut.,) 



c, ; sol,, mi 



3) 



53,508. Resonance Tube on Base, can be closed at one end, Figure 



With this resonance tube, which replapes the labial pipe, it is explained that when the pipe is open 

 the overtones are the even quadruples of the fundamental tone, and when the pipe is closed, that the 

 overtones are the odd quadruples of the fundamental tone, and that the fundamental tone of the open 

 pipe is the octave of the fundamental tone given by the covered pipe of equal length. The open pipe 

 vibrates therefore in a half wave, the covered pipe in a quarter wave. 



Tne lube is tuned in such manner that when closed on one side it gives the fundamental tone c t 

 (ut 3 ) clearly and resonantly. For this purpose the tuning fork Cj (ut s ) is struck smartly and held in front 

 of the free aperture. Even with tuning fork g 2 (so! 4 ) (the overtone with thrice the number of vibrations) 

 the tube resonates clearly, while it does not resonate with fork c 2 (ut 4 ), the octave of the fundamental 

 tone. Tais, however, becomes the case when the resonator tube is opened so that it corresponds to the 

 open labial pipe, which gives a tone twice as high as the covered pipe of the same length. 



.->:>. .in!). Tuning Fork for above, Ci = 256 compound vibrations (ut 3 = 512 v. s.), with handle 



.").'{..") 10. id em, c 2 = 512 compound vibrations (ut, = 1024 v. s.), with handle 



.">:'.. ."ill. idem, g, = 768 compound vibrations (sol, = 1536 v. s.), with handle 



30. 0.0 



s. d. 



9. 0. 



74. 6. 



0. 12. 



1. 8.0 



o. o 



18. 

 18 



Cl. 4693, 1105. 



29 



