426 



Acoustics. 



No. 53233 



53 234. 1 : 9. 



53 233. 1 : 10 



53242. 1:8. 



53 235. 1 : 5. 



53 238. 1 : 7. 



53238a. 1:4. 



53.233. Acoustic Bellows after Bertram, Figure, hand driven, with four valves and a * '' 

 tube attachment for taking reed pipes 3.0.0 



53.234. Wind Pressure Regulator for Sirens, Figure 1. 16. 



The apparatus is employed for lessening the impulses which cannot to be entirely avoided when 

 foot bellows are used. 



53.235. Wind Chest, Figure, with four valves, for placing on the blowing table having 



no valves or for use in conjunction with the water jet blower l. r_'. o 



The Wind Chest can also be worked with compressed air from steel bombs. In this case the 

 following are necessary: 1 Steel Bomb No. 50,947 ( 1. 16. 0), 1 pressure reducing valve No. 50,953 

 ( 2. 5. 0). The cost of charging the bomb (No. 50,947) is 0. 10. 0. 



53.236. - - idem, with eight valves 2. 10. 



53.237. - - idem, with thirteen valves 4. 0. 



Vibrating Air Columns, Pipes, Sound Analysis. 



53.238. 4 Tubes with pistons, Figure, giving a chord when the pistons are successively 



drawn out 1. 16. 



53,238 a. 3 Covered Pipes, Figure, of metal, with wood mouthpiece, for the tones c 8 = 1024, 



C 4 = 2048 and c 5 = 4096 vibrations (ut s = 2048 v. s., ut 6 = 4096 v. s., ut 7 = 8192 v. s.) 0. 18. 



53.239. Labial Pipe of wood, to be used open and closed 0. 10. 



53.240. of tin, cf. Fig. 53,245 0. 8. 



53.241. - - of wood, with middle slide, giving the same tone open and closed 0. 16. 



Cl. 5992, 5996, 1083, 

 1066, 4099, 5054. 



