Xo. 53417. 



Standard Tuning Forks on Resonance Boxes. Standard Tuning Forks with Sliding Weights. 



439 



53415. 1 : 8. 



53417. 1 : 6. 



.">:>.. 'JUS. Large Tuning Fork for 16 24 vibrations, c- 3 g- 3 (ut- 2 sol-.,), F i g u r e, for deter- 

 mining the limit of audibility of the deepest tones 



.~>3,3!Mi. - - idem, smaller 



Tuning Forks with sliding weight for Bezold's continuous progression of tones, for testing 

 the sensitivity of the ear to sound, Figure 53,404. 



List No. 

 < 'ompound vibrations 



V. s. 



Tone Compass j 

 Pitch, unloadedj 



These tuning forks sound without harmonics when the sliding weight is placed on same, and are 

 used for qualitative and quantitative audibility testing from below the limit of audibility onwards; for 

 the entire compass to the higher limit of audibility the entire continuous progression of tone (Bezold's) 

 No. 53,473 is employed. 



The prongs of these tuning forks are marked with the number of vibrations and the tones for the 

 cm responding positions of the sliding weights. 



List No. 53406 

 Compound vibrations 153 217 

 V. s. 306434 



_, ( d# a 



Tone Compass ( re# la 



Pitch, unloaded i 

 



ut 3 

 1.5.0 



The prongs of these forks are marked with the tones for the corresponding positions of the sliding 

 weight. 



s. d. 

 12. 0. 



10. 0.0 





:> 1.411. Drumstick for striking Tuning Forks Nos. 53,40653,410 0. 5. 



.VI. 112. Tuning Fork b b , (si" 3 ), for resonance of the oral cavity (W. D. p. 312 [285]) . . 0. I.u 

 53,413. 5 Tuning Forks with resonators, Figure, sounding with the vowels a, e, i, o, u 7. 0. 



5:3,414. Tuning Fork with Resonator, Figure, pitch aj with 435 compound vibrations 



(ut 3 = 870 v. s.), the tuning fork is marked with the nodal point (W. D. Fig. 217 [203]) o. ir>. (i 



53,415. Standard Fork with Resonator, Figure, mounted together on iron base, c t = 256 



compound vibrations (ut 3 = 512 v. s.) 5. o. o 



.").'). 4 17. Tuning Fork with Electromagnetic Drive and with sliding weights, for varying the 



pitch by reducing the size of the orifice, with resonator of variable pitch F i g u r e 5. 0. 



The tuning fork can be adjusted to the tones between d*j and a l (re# 3 and Ia 3 ). The pitch of the 

 is varied by an iris diaphragm placed in front of its aperture. 



Cl. 1135, 3894. 



