412 



THE VOICE 



2,500 ergs per second ; and for tub oratory ])robably five times 

 that amount. 



R. L. Jones (Amer. Telegraph Co.) considers that the energy 

 actually emitted in speech is very small. He calculates that if a 

 million persons were to talk steadily, and the energy of their voices 

 were to be converted into heat, they would have to talk for an 

 hour and a half to produce enough heat to boil half a pint of water. 



Sabine, who experimented largely with organ pipes as his source 

 of sound, found that an open diapason organ pipe at a wind 

 pressure of 9-14 grams per sq. cm. emitted 1,400 to 32,000 ergs per 

 second according to the pitch of the note. 



Table LXIV. gives the relative values of the expenditure of 

 energy in the utterance of a single perceptible note in various 

 sizes of halls. The notes were produced by an artificial larynx 

 (syren). 



TABLE LXIV 



These figures, multiplied by 2 X 10 ~\ give, in kilogram-metres per 

 second, the minimum expenditure of energy necessary to make the sound 

 perceptible in ten different parts of the hall. 



In every case the possessor of a bass voice has to expend more 

 energy than the baritone or tenor. Generally speaking, the tenor 

 has least trouble in making himself audible, but instances may occur 

 where, on account of its resonating qualities, a building may prove 

 more suitable for a baritone than for the former. 



