No. 53314. 



Stroboscopic Discs. Flame Manometers. Vibrating Bars. 



433 



53 309, 53 304. 1 : 8. 



53 313. 1 : 6. 



53 308. 1 : 8. 



53 311. 1 : 9. 



53314. 1:10. 



s. d. 



r>2,<>33. Gas Flame Manometer after Weinhold, as No. 53,307, suitable for the whirling table 1. 4. 



.Vi.. 'iox. -- idem, Figure, with a rotating mirror; the two mounted on one stand . . 2. 0. 

 The manometer is constructed in accordance with Figure 53,306. 



53.309. Mach's Organ Pipe for the stroboscopic demonstration of the vibrations of an air 

 column, cf. Figure (M. P. I, p. 669 [739]), without stroboscopic disc or electric motor ' "> 



The pipe has a membrane at the position of the nodal point corresponding to the fundamental 

 tone; this membrane holds off the air current from the halves of the pipe, glazed on two sides, and situated 

 between this nodal point and the end. A platinum wire is stretched in the interior of the pipe and connected 

 with two external terminals, plainly visible in the Figure. If a small sponge, fixed on a glass rod and satu- 

 rated with sulphuric acid is passed over the wire and the wire heated by an electric current, the vibrations 

 can be observed from the vapours given off, by means of an intermittent light. Tne intermittent illu- 

 mination is obtained with the Stroboscopic Disc No. 53 304 or with Tuning Fork No. 53 310. 



53.310. Stroboscopic Tuning Fork c = 128 vibrations (ut 2 = 256 v. s.), with electric drive, with 

 two diaphragms, on stand 



Vibrating Bars, Velocity of Sound. 



53.311. Apparatus for the Longitudinal Vibration of Bars, Figure (M. P. I, Fig. 761 [785]) 



53.312. 4 Wood Bars, which sound a chord when thrown on the ground 



2. 8. 



4. 10. 





0. 8.0 



0. 3.0 



53.313. 8 Wood Bars, giving the gamut, Figure 0. 6. 



53.314. Apparatus for showing the Expansion and Contraction of a Longitudinally Vibrating 



Bar, after Koenig (Tyndall, Schall [Sound], Fig. 82) j 1. 16. 



CI. 1116, 1117a, 



1080, 5997, 6017. 28 



