452 



Acoustics. 



No. 53524- 



53 524. 1 : 5. 



53 528. 1 : 7. 



* 53,524. Apparatus for Demonstrating the Lissajous Figures by means of vibrating springs 



with mirrors, Figure, with electromagnetic drive in order to maintain the vibrations 



to any length of time 4. 16. 



53,525. - - idem, without electromagnetic drive . 2. 0. 



* 53,526. - - idem, after Pfaundler, with two vibrating steel springs and crossed gaps (M. P. I, 



Fig. 702 [726]), one spring with variable time of vibration i 1. 4. 



53.528. Electric Glow Lamp with straight Filament, Figure, on stand, with shielding 

 chimney and small hole, for use with preceding apparatuses or with the following Tuning- 

 Fork Apparatuses 0. 18. 



The working voltage should be quoted when ordering. If this is not given we supply the lamp for 

 110 volts. 



53.529. Tuning Fork Apparatus for subjectively and objectively demonstrating the Lissajous 

 Curves (W. I). Fig. 236 [222]), with two massive tuning forks < = 128 compound vi- 

 brations (ut., = 256 v. s.), one fork with sliding weights, with glass mirrors, on polished 



wood stand 5. 0. 



53.530. The same Apparatus, Figure, both forks with electromagnetic drive 8. 0. 



53.531. The same Apparatus, with thoroughly well ground steel mirrors, without electro- 

 magnetic drive (i. 0. 



32. - idem, with steel mirrors and with electromagnetic drive for both forks . . 0. 0.0 

 Tuning Forks for above for demonstrating the curves (Lissajous) of varions phase-differences (M. P. 1. l-'ig. 71!i). 



53,533. Phase Differences, 1 



53,534. 



53,535. 



63,536 



63,638. 



53,53!). 



Compel Vib., 



(b) With (Mass 



Mirror 



hi. i) 



in. (i 

 Hi. ii 

 in. ii 

 Ki. (i 

 in. ii 



14. 



Tiic forks listed give together with one of the forks < = 128 compound vibrations int, '-'."ili v. s.) of the 

 Apparatus No. 53,529 63,632, tne pha.-.e differences mentioned. 



53,540. 2 Tuning Forks on Stands, mounted vertically and the Forks provided with glass * s <i- 

 mirrors, for demonstrating the figures, by means of sunlight, on llic wall (M. I'. I. 

 Fig. 808 [832]) ................................ 5. 0. 



0.0 



* 53,541. Tuning Fork Apparatus for subjective and objective Demonstration of the 



Curves, Figure, with case for the tuning forks ................ 13. 



On an iron stand ;ire fitted two tuning forks < = 128 compound vibrations int., _'.">(> v. s.). one' 

 in a horizontal and the other in a vertical position. Tne Tuning Forks have limbs -J.'id mm buig and give 



* Can lie used with the Projection Apparatus. 



CI. 3890, 3875. 



