M. Savart on the Improvement tftJie Pipes of Organs. 81 



side which carries the bevel. Nay, it may differ very much 

 from this. If, for example, we take a prismatic square tube 

 in which a piston moves, the length of the column will be the 

 distance of the piston from the base of the tube, provided this 

 distance is greater than the side of the base of the prism of air ; 

 but if it becomes less, the true length of the column of air is 

 the small side of the base of the prism. 



In general, when we cause air to sound in any vessel, the 

 depth of the vessel ought to be taken as the length of the co- 

 lumn of air, when its diameter is smaller than its depth, but 

 when this diameter is greater than its own length, it becomes 

 that of the column of air. If, for example, we place a small thin 

 plate of wood or white-iron, or even the blade of a knife, on 

 the orifice of a vessel with a narrow neck like a bottle, or a 

 caraffe, and if we blow the air against the edge of the plate, 

 either with a small port-vent, or with the mouth itself, we 

 shall hear a sound which is in general very grave ; but we 

 must not suppose that the diameter of these vessels should be 

 taken for the length of the column of air, this length being 

 equal to the height of the vessel. With respect to the grate- 

 ness of the sound, it depends on the length of the column of 

 air, on its diameter, and on the small extent of the embouchure. 

 Cubical pipes emit sounds extremely pure, and of a particu- 

 lar timbre : They speak with a facility and a promptitude quite 

 astonishing, and may be employed in the construction of or- 

 gans. They will also have the advantage of occupying 

 little room, at least for the highest octaves. The sound n 

 is given by a cube oneof whose sides is from 53 to 54 lines, 

 whilst the bourdon, which gives the same sound, is commonly 

 from 10 to 11 inches long, and having one of its sides from 

 2 to %\ inches. Hence it may be seen, that the sound of a 

 cube of air, made to vibrate by one of its edges, is much more 

 grave than if it were made to vibrate throughout the whole 

 extent of one of its faces; for a column of air 54 lines long, 

 shut up at one end, and made to vibrate with a full orifice, 

 will give the souik1/«, which is an octave and a quarter more 

 acute than the sound ut, which is yielded by a cube of 54 

 lines made to vibrate partially. Whence it is easy to con- 

 clude, that we may pass from the sound of a cube of air to that 

 vol. in. no. 1. JAN. 182G. V 



