124 Mr. D. J. Blaikley on Brass Wind 



arranged that there shall be a node for every note of the har- 

 monic series at the mouthpiece as required ; and according as 

 that is more or less perfectly effected will the instrument be 

 more or less perfectly in tune. This bugle is divided into its 

 seven semi- ventral segments for its 4th note, c 512, according 

 to the diagram ; and it will be found that by blowing at any 

 one of the nodal points, with any length of the bugle contain- 

 ing an odd number of semi- ventral segments, the note c" can 

 be produced. The total number of pieces and combinations 

 that can give this note is eighteen. 



Having given these few illustrations of the conditions upon 

 which correct intonation, or the relative pitch of the different 

 notes that can be sounded on a brass instrument, depends, I 

 will now endeavour to show the connexion there is between 

 this point and the question of quality of tone, understanding 

 by quality of tone that characteristic of sound which enables 

 us to recognize a difference between tones of the same pitch. 

 Helmholtz has fully demonstrated that it is only in exceptional 

 cases that we hear a simple musical tone — the vast majority of 

 musical tones being in reality compound tones, in which the 

 fundamental or prime tone has blended with it many upper 

 partial tones of the natural harmonic series, — and that the 

 variety of quality of tone depends mainly upon the number 

 and intensity of these upper partial tones. Blowing the note 

 c 256 on three resonators of different forms we get three di- 

 stinctly different qualities of tone : the resonators now used 

 are a. common paraffin-lamp chimney, the conic frustum 

 already shown (having for its first two proper tones d and c"#), 

 and the bugle. Analyzing these three tones by tuning-forks 

 or resonators, we find that the lamp-chimney of irregular form 

 gives no upper partials ; the tone is pure or simple. The cone 

 has the second and third partials sounding, but not strongly, 

 as it is not strictly in tune for them, or, in other words, there 

 is a difference of phase between the prime tone and the par- 

 tials. And the bugle has all the partials up to the seventh, 

 gradually diminishing in power, but all tolerably strong up to 

 the fifth inclusive. Slightly altering the form of the cone by 

 adding tubing to the narrow end, and maintaining the original 

 pitch of the prime tone (c 256), by cutting a portion off the wide 

 end the pitch of the second tone may be altered until it is 

 c 512, an exact octave from the prime; and we find that the 

 quality of tone of the prime or fundamental note is altered, 

 owing to the more perfect resonance which the cone now gives 

 to its second partial. In its original form, with proper tones 

 ('!-<:%" ', the cone could give but an imperfect resonance to d' y 

 the second partial to its prime d. 



