176 Miscellaneous Intelligence. 



equal obliquity, but in an opposite direction. The obliquity is not 

 necessary to the production of sound, but it serves to give 

 motion to the plate by the passing air. The box is connected 

 by a tube with a bellows, that supplies it with air. 



In the experiments made to ascertain the vibrations for each 

 sound, the plate was made to revolve, by wheel-work, put in 

 motion by a weight ; the bellows were then put in action, only 

 for the purpose of judging whether the sounds of the machine 

 accorded with the notes of a standard instrument. This in- 

 strument was the harmonica, consisting of an arrangement of 

 iron or steel bars, made to vibrate by a bow. 



Thus disposed, the machine was made to produce the dia- 

 tonic notes of the gamut, and even some beyond them ; the 

 revolutions of the plate were estimated by the revolutions of a 

 wheel, which turned with a velocity thirteen times and a half 

 less than that of the plate. 



The following table is the result of these experiments, but 

 the inventor of the instrument intends to refine and improve 

 his machinery, and then repeat and extend them. 



No. of revolutions No. of revolmiom No. of vibratiom 



Notes. made by the made by the produced 



wheel in 1'. plate in 1". in 1". 



la 19 4jVo 427 



si 211 4-1'^^ 477 



ut 22f 5,Vo 511 



re 



mi 



25 5/oV 567 



28 6/^0. 630 



fa 30 6,Vff 675 



sol 34 7,6^ 765 . 



la 38 8f^^ 855 



si 42^ 9^55^ 955 



ut 45| IOtV? 1023 



re 50 U^^^ 1125 



The first la corresponds to the second of the harmonica, and 



is the unison of the common diapason. 

 If water be passed into the Siren in place of air, it produces 



sound, even though the whole instrument be immersed ; and 



