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A New Form of 



DEMONSTRATION 



ORGAN 



PIPE 



Special Features 



Suggested^by 



PROFESSOR LUNN 



University I of Chicago 



No. 3268. DEMONSTRATION ORGAN PIPE. All Metal. Making it possible to teach all the 

 fundamentals underlying organ building. 



The usual method of varying the length of a closed pipe is by a sliding piston. Frequently in 

 demonstrating this by sliding the piston it is found that one of the overtones will become more marked 

 than the fundamental and the pipe apparently changes pitch. This may sometimes be delayed by blow- 

 ing either more or less vehemently. But it has been proven that with the range of lengths usually used 

 in class demonstration work, it is impossible to make an organ pipe that will not emphasize some over- 

 tone at some length. To produce the fundamental at different lengths the mouth piece must be changed 

 in construction. 



This instrument has an adjustable mouthpiece. By operating the two sliding cylindrical sleeves 

 the amount and direction of the air jet may be changed and also the size of the opening between the 

 resonance column and the outside air. 



By this method a demonstration of the law of lengths may be made without producing overtones 



— by adjusting the mouthpiece while operating the piston. 



Further, the overtones, first, second, third, etc., may be produced at will, without changing the 

 blowing or the length of the resonance column. This demonstrates one of the most technical problems 

 in the art of organ building, and also shows very forcibly the reason for so-called "lip-positions" in 

 many wind instruments. 



Handsomely nickel-plated. About 60 cm. long. 



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W. M. WELCH SCIENTIFIC COMPANY 



Manufacturer, Importer and Exporters of Scientific Apparatus 



1516 Orleans Street CHICAGO, ILL., U.S. A. 



