f - !tANS OF HEARING AND OF THE VOICE. 201 



A pure atmosphere in a room for speaking, being favorable 



pu'rl atmos* to the speaker's health and strength, will give him greater 



phereinaroom power of voice and more endurance, thus indirectly improv- 



a o • .^^ ^^^ hearing by strengthening the source of sound, and also 



by enabhng the hearer to give his attention for a longer period undisturbed. 



In constructing a room for public speaking, the ceding 

 How should a , . , , -.nn^n-c^.-r.-uj. 



room for pub- Ought not to exceed 30 to 3o leet m height. 



lie speaking be ^fj^Q reason of tliis may be explained as follows: — If wo 



constructed 7 , ,, , , t ■ ^ ^ ^ 



advance toward a waU on a calm day, producmg at each step 



"^^"^^ ^LJ^t some sound, we will find a point at which the echo ceases 

 reasoaof taisr ' ' . j mi j- 



to be distinguishable from the origmal sound. Ihe distance 



from the wall, or the corresponding interval of time, has been called the limit 

 of perceptibility. This limit is about 30 to 35 feet; and if the ceiling of a 

 building for speaking be arranged at this limit, the sound of the voice and the 

 echo will blend together, and thus strengthen the voice of the speaker. 



If the ceiling be constructed higlier than this limit of perceptibihty, or 

 higher than 30 or 35 feet, the direct sound and the echo will be heard sepa- 

 rately, and will produce indistinctness. 



„ Echoes from walls and ceilings may, to a certain extent, 



How may , ■ , j 



echoes in a- be avoided by covering their surfaces with thick drapery, 



partments to ^j^j^j^ absorbs sound, and docs not reflect it. 



Bonie extent ' 



be avoided ? If the room is not very large, a curtain behind the speaker 



impedes rather than assists his voice, 

 by^^the^key- ^^^- ^'^ ^^^^J apartment, owing to the peculiar arrange- 



note of an ment of the reflecting surfaces, some notes or tones can be 



heard with greater distinctness than others; or, in other 

 words, every apartment is fitted to reproduce a certain note, called the key- 

 note, better than any other. If a speaker, therefore, wOl adapt the tones of 

 his voice to coincide with this key-note, which may readily be determined 

 by a little practice, he will be enabled to speak -with greater ease and distinct- 

 ness than under any other circumstances. 



In a large room nearly square, the best place to speak from is near one cor- 

 ner, with the voice directed diagonally to the opposite corner. In most cases, 

 the lowest pitch of voice that will reach across the room wiU be the most 

 audible. In all rooms of ordinary form, it is better to speak along the length 

 of a room than across it. It is better, generally, to speak from pretty near a 

 wall or pillar, than far away from it. 



SECTION III. 



ORGANS OF HEARING AND OF THE VOICE. 



437. The Ear consists, in the first instance, of a funnel, 

 construction of shaped mouth, placed upon the external surface of the head, 

 the human ear. jj^ many animals this is movable, so that they can direct it 

 to the place from whence the sound comes. It is represented at a, Fig. 194. 



9* 



