271 Mr. C, W. H. Foord on Air-Pressures 



ordinates of the curves are the manometer pressures in 

 inches of water, this being the usual mode of measuring 

 wind-pressures for organ-pipes ; while the abscissae represent 

 the musical intervals according to equal temperament. The 

 D in brackets is middle C on the piano, the notes being as 

 written for the instrument, and hence being a tone lower 

 than the actual sounds produced, owing to the instrument 

 being in B|?. 



It will be seen, from an examination of the figures in the 

 above table and the corresponding curves, that the general 

 tendency is for the pressures to fall as the pitch rises. This 

 result is the reverse of that recorded by Dr. Barton and 

 Mr. Laws for the trumpet, cornet, and trombone, but agrees 

 substantially with the figures for the clarinet given in 

 Dr. Stone's original table. It will be noticed, however, that 

 a temporary rise of pressure occurs at the second BtJ; this 

 note being the first note obtained after opening the twelfth 

 or harmonic key and forming the first note of the so-called 

 clarion register. 



Results of Experiments on the Saxophone. 



The instrument used for these experiments was an Ef> 

 alto Saxophone tuned to the high concert or military band 

 pitch, and made by Hawkes & Son, London. The experi- 

 ments to be described were made with the single reed proper 

 to the instrument, and also with a bassoon reed which has 

 double blades. The latter reed was adapted to the instru- 

 ment by removing the mouthpiece and substituting a piece 

 of cork hollowed out to carry the reed and fit the end of the 

 instrument. The mode of tabulating and plotting the results 

 is the same as lhat adopted for the clarinet. The A in 

 brackets corresponds to middle C on the piano. 



The results obtained with the saxophone are interesting, 

 as they indicate that it is the form of reed which is the 

 important element as regards the pressures employed in 

 playing. It might be thought, from the figures in Dr. Stone's 

 table (which does not include the saxophone), that as the 

 only instrument there mentioned in which the pressures do 

 not increase with rise of pitch is the clarinet, this peculiarity 

 is confined to the clarinet and is perhaps due to its cylin- 

 drical bore. It will be seen, however, from an examination 

 of the tables and curves for the saxophone when using the 

 proper single reed, that the pressures at the beginning and 

 end of the scales are practically equal, the maximum 

 pressure, at any rate when playing loudly, being at the note 

 D about half-way through the scale. It is at this note that 



