506 VOICE AND SPEECH. 



and it is probably in great part by the action of these mus- 

 cles that the varied and delicate modifications in the rigidity 

 of the vocal chords are produced. 



The remarkable differences in singers in the purity of 

 their tones are undoubtedly due in greatest part to the un- 

 swerving accuracy with which some put the vocal chords 

 upon the stretch ; while in those in whom the tones are of 

 inferior quality, the action of the muscles is more or less 

 vacillating, and the tension is frequently incorrect. The 

 fact that some celebrated singers can make their voice heard 

 above the combined sounds from a large chorus and orchestra 

 is not due entirely to the intensity of the sound, but in a 

 great measure to the absolute mathematical equality of the 

 sonorous vibrations, and the comparative absence of discord- 

 ant waves. 1 Musicians who have heard the voice of the 

 celebrated basso, Lablache, all bear testimony to the re- 

 markable quality of his voice, which could be heard at times 

 above a powerful chorus and orchestra. A grand illustration 

 of this occurred at the musical festival at Boston, in 1869. 

 In some of the solos by Mine. Parepa-Rosa, accompanied by 

 a chorus of nearly twelve thousand, with an orchestra of 

 more than a thousand and largely composed of brass instru- 

 ments, we distinctly heard the pure and just notes of this 

 remarkable soprano, standing alone, as it were, against the 

 entire choral and instrumental force ; and this in an im- 

 mense building containing an audien.ce of forty thousand 

 persons. The absolute accuracy of the tone was undoubt- 

 edly an important element in its remarkably penetrating 



1 Immense progress has been made in the analytical study of different 

 sounds by the celebrated German physicist, Hehnholtz. By means of his in- 

 geniously-constructed resonators, taking advantage of the laws of consonance, 

 in accordance with which the quality as well as the pitch of different tones is 

 reproduced, he has been able to separate sounds into their different component 

 parts as accurately as a ponderable compound is resolved into its constituent 

 elements in the laboratory of the chemist. (HELMHOLTZ, Theorie physiologique 

 de la musique fondee sur V etude des sensations auditives, Paris, 1868, p. 48, etseq.) 

 This subject will be fully considered under the head of audition. 



