No. 53575. 



Recording Tuning Forks, Phonautographs, Vibration Microscopes. 



457 



53570. 1:14. 



53 575 A. 1:8. 



53 574. 1 : 6. 



53 575 B. 1 



having a style. The vibrations of a tone acting on the membrane are recorded along with the curve s. d. 

 of the fork having a known frequency, thus rendering it possible to determine the vibrations of a tone. 

 Fortuning forks with other frequencies: see Nos. 53,553 53,558. 



53,573. Phonautograph after Scott, without tuning forks (M. P. I, Fig. 804 [828]) .... 



53,57-4. Vibration Microscope after von Helmholtz, Figure (Lissajous's Improved Com- 

 parator), with a very massive tuning fork c = 128 compound vibrations (ut 2 = 256 v. s.), 

 with electromagnetic drive for permanently maintaining the vibrations and with two 

 sliders for varying the pitch (M. P. I, Fig. 701 [725]) 



21. 0.0 



7. 10.0 



53,575. --idem, Figures A and B, with two stands and five massive tuning forks, 



each provided with objective, steel mirror and slider 33. 0. 



All tuning forks are arranged for working with electromagnets; the two electromagnets and the 

 forks can be adjusted; the eyepiece also is adjustable vertically and horizontally by micrometer 



Cl. 3380, 1170, 

 1169, 1171. 



