456 



Acoustics. 



No. 53 561 



53564. 1:11. 



53 568. 1 : 7. 



53 567. 1 = 7. 



53.561. 2 Tuning Forks with Recording Device on Wood Stand, c = 128 compound vibrations s. d. 

 (ut, = 256 v. s.), one fork fixed, the other movable and provided with sliders for gra- 

 phically demonstrating the vibrations of two tuning forks (M. P. I, Figs. 806 and 807 i 



[830 and 831]) 6. 0. 



By means of the sliders one fork can be altered in relation to the other by 4 : 5. 



53.562. Forks for above with different number of vibrations Each 1. 10. 



53.563. 2 Tuning Forks with Recording Device, large pattern, on Iron Stand, cf . Figure 53,564 i 



with two forks, c =128 compound vibrations (ut 2 = 256 v. s.) 10. 0. o 



53.564. - - idem, with electromagnetic drive for both forks, Figure 13. 0. 



53,56o. Forks for above, of different frequency Each 2. (i. <> 



53.567. Vibrograph after Duhamel, Figure, for determining graphically the frequencies 



of tuning forks (Pisko, Die neueren Apparate der Akustik, Fig. 11) 3. 0. 



53.568. Recording Drum with Clockwork, F i g u r e, can be used vertically and horizontally ; 

 speed variable from 40 1 / 2 mm per second by friction; the drum can be moved along 



the axis and easily removed 6. 0. 



53.569. idem, wit-h electric contact >. 1<>. i> 



53.570. Phonautograph after Konig, with tuning fork stand, Figure (M. P. I, Fig. 668 



[694]). Price without forks 11. 0. 



The tuning forks to use are the chronographic forks with electromagnetic drive. \<>s. ~>3,553 53. .v.s 



Tne tuniiii; lurk curves can also be taken on sensitied paper and fixed permanently in accordance 

 with Nimt'iilir's process (Drudes . \mialen der I'liysik. IV.. I'.ioii. Vol. 111. p. tiJTl. 



53.571. Phonautographic Cylinder alone, on iron stand, sec Figure 53,570; without base- 

 plate, tuning fork stand or tuning forks !t. n. (i 



53,57'-'. Membrane Phonautograph after Scott and Konig (with comparison tuning forks). 



(Pisko, neuere Apparate Fig. 23) -'">. 



A tmiinu lork of c, --'."Hi riini|miuid vibrations iul : , ~>\- V. %.) with style U placed in Iiout ol' 

 the movable cylinder. liehind the fork is a parabolic Inline], do-ed with a membrane, t lie latter also 



Cl. 5515, 



5357. 3379. 



