418 



Acoustics. 



No. 53183 



53 183. 1 : 4. 



53 187. 1 = 5 



53 189. 1 : 



53 184. 1 : 9. 



53 185. 1 : 6. 



53 186. 1 : 4. 



53 191. 1 : 4. 



Acoustics. 



Propagation of Sound, Pressure Changes, Reflection, 



and Refraction of Sound. 



Bell with Clockwork for proving that air carries the sound waves, for placing under air pump 

 receivers, see Nos. 53,069 53,071 on p. 405, also electric bell in receiver, No. 53,072. 



53,183. 2 String Telephones, Figure (W. D. Fig. 204 [190]) 



53.184. Apparatus for demonstrating the Propagation of Sound in Liquids and Solids, F i g u r < 

 (Tyndall, Sound [der Schall], Fig. 28), comprising resonance box with attachments 

 and tuning fork 



The tuning fork is struck or bowed after being, together with its small wood base, screwed off 

 the sound box, the sound, however, being scarcely audible. If it is now placed upon the box or on one 

 of the wood or brass rods screwed to the box, the sound is considerably intensified. This intensifi- 

 cation of sound also takes place when the tuning fork (together with wood base) is placed in the funnel 

 of the glass tube, filled with water, and screwed on to the sound box, even though the wood base of 

 the fork be not in contact with the wall of the funnel. 



53.185. Sensitive Flame Burner, after Konig, Figure, working with certainty with the 



usual gas pressure of 35 mm 



53,186. - - idem, after Weinhold, simpler, Figure, with wire net, without sound horn 



53,187. idem, after Weinhold (W. D. Fig. 198 [183]), Figure . 

 For rubber bags for the latter apparatus, see Nos. 51,267 51,270, p. 21-2. 



s. d. 



0. 8.0 



1. 10. (I 



1. 0.0 

 0. 8.0 



0. 6.0 



Cl. 5857. 1018, 1040,5788, 

 1038, 1039, 1759. 



