438 



Acoustics. 



No. 53374 



53381. 1:6. 53382. 1:6. 



53383. 1:4. 



53398. 1: 12. 53404. 1 : 4. 



53413. 1 : 5. 



Standard Forks on Resonance Boxes. 



List No. 53 374 53 375 53 376 



a, = 435 



lit, = 256 

 2. 0. 



ut 3 = 512 

 1. 16. 



la, = 870 



53377 



<= 512 



utj = 1024 



1. 10. 



53378 



f,= 1024 

 ut 6 = 2048 

 1. 10. 



53414. l : 7. 



53379 



c 4 = 2048 compound vibrations 

 ut 6 = 4096 v. s. 

 1. 10. 



8. (1. 



1. 10. 



The Standard Forks are very specially and carefully constructed and finely polished 

 to prevent oxidation. 



53.380. Containing Box for one of the tuning forks Nos. 53,374 53,379 1. 



53.381. Tuning Fork c t = 256 compound vibrations (ut s = 512 v. s.), on Resonance Box. 

 Figure, with detachable electromagnetic drive 2. 8. o 



53.382. -- idem, & l = 435 compound vibrations, Figure (Ia 3 =870 v. s.) 2. 6. 



.").;.. '583. 2 Large Tuning Forks, Figure, with sliding weights, on hollow wood base, tor 



producing the chromatic scale Cj c 2 (ut 3 ut 4 ), International Pitch 3. 0. o 



14 Tuning Forks with sliding weights, cf. Figure 53,383, for producing the tones and semi- 

 tones from c 1 tog 3 (utj sol-), in International Pitch, for testing church bells for their 



53387 



ut., mij 

 2. 4.0 

 53394 



er-g+i 



ni 4 sol* 

 2.0.0 



For testing a cliuivli l>dl ;^ rcicards it.- nvcrtcincs. .-i fork is struck and placed with the hollow li.-i-e 

 on the edge of the bell. It the overtone is present the hell rings. 



{, 307 a. Containing Case for above, sufficient for 5 Forks 



1. s. (i 



Cl. 1129 29a. 1123, 1134, 3376. 

 '.132, 3374. 



