410 



would at the same time increase the number of pulsations, and so 

 raise the tone ; but to prevent this, the glottis must at the same 

 time be lengthened, and vice versa ; or, in other words, that the dif- 

 ferent lengths of the glottis can, under different degrees of pressure, 

 produce the same number of shocks, but at different degrees of 

 intensity. 



Of the Qualities of the Voice. 



Various simultaneous causes modify the qualities of the voice : 

 1, according as the glottis partially or entirely closes the passage 

 between the explosions, it produces veiled or brilliant sounds ; 2, the 

 tube which surmounts and surrounds it also greatly affects the 

 quality of the voice ; by its contractions it gives brilliancy to it and 

 its widening volume ; 3, the epiglottis also plays a very important 

 part, for every time that it lowers itself, and nearly closes the orifice 

 of the larynx, the voice gains in brilliancy ; and when, on the other 

 hand, it is drawn up, the voice immediately becomes veiled. 



