CHAP, i.] SOUND SIGNALS. 115 



V. ACOUSTICS APPLIED TO ARCHITECTURE. 



One of the most important applications which can be made of 

 the laws of acoustics is that of the construction and arrangement 

 of large public buildings. With respect to these, numerous attempts 

 have been made, but few have succeeded, and the reason is doubtless 

 that the architects who have tried them were more engrossed with the 

 question of art than that of science ; perhaps also the want of special 

 knowledge has had a great deal to do with this almost general 

 failure. 



Public assembly-rooms may be divided into three categories, the 

 requirements of each not being the same in an acoustic point of view. 

 First of all, there are concert-rooms for which clear and distinct 

 hearing is the principal object : the orchestra and the spot where 

 the singers are placed form the sound focus, whence diverge all the 

 waves which ought to strike the listener's ear, wherever he is seated, 

 under the best conditions, so that the finest shades of the melody 

 may be perceptible to him without losing the haimony of the 

 whole. Here sight may be sacrificed to the ear, as it is not pro- 

 perly speaking a spectacle, and all is confined to the hearing of 

 a piece of music. Chance has sometimes united these conditions, 

 and the concert-room of Music in Paris of the Conservatoire is an 

 example of it, according to the general testimony of amateurs and 

 artistes. 



Lyrical theatres form an intermediate category between concert- 

 rooms and those intended only for listening to an orator or actors. 

 Music is here again the principal object, but the problem is compli- 

 cated by the necessity of leaving the stage visible to all the spectators. 

 Moreover, the sound-focus is here double, for it consists, on the one 

 hand, of the orchestra, and, on the other, of the stage where the 

 singers are placed. The ordinary comic or dramatic theatres are 

 almost in the same difficulty. 



Halls for courts and deliberating assemblies form the third class 

 of places of meeting. Here the distinctness of hearing is the first 

 and nearly the only difficulty to solve, as the room is not extensive 

 enough for the sound-waves to lose their intensity before they reach 

 the most distant hearer. 



