CONCERT-ROOM ACOUSTICS. 235 



notes of the singer or player echoed by such regularly 

 vibrating walls and ceiling. 



If, again, the velarium and side drapery of the transept 

 and orchestra had been thick, soft woollen cloths, the 

 sound, like the light, would have been absorbed or "muf- 

 fled," and, though very clear, it would be weak and insuf- 

 ficient. 



The reader will now ask What, then, is the right ma- 

 terial for such velarium and walls? I cannot pretend to 

 say what is the best possible, believing that it has yet to be 

 discovered. The best yet known, and attainable at moder- 

 ate expense, is common canvas or calico, washed or painted 

 over with a mixture of size and lime, or other attainable 

 material that will fill up the pores of the fabric, and give it 

 a moderately smooth face or surface. Thus prepared, it is 

 found to reflect sound, as paper, ground glass, etc., reflect 

 light, by scattering reverberation, but without definite 

 echo. 



It will now be understood how the velarium acted in 

 rendering the solos so clearly audible at the great height 

 and distance of the Upper Press Gallery. Instead of being 

 wasted by diffusion in the great vault above,, they were 

 stopped and reflected by the velarium, but not so reflected 

 as to produce disagreeable repetition notes, just audible at 

 particular points, as the lights of the mirror reflections of 

 the chandeliers would be. 



Flat surfaces reflect radially, while concave surfaces with 

 certain curves reflect sound, light, heat, etc., in parallel 

 lines. The walls and roof of a music-hall should scatter 

 their reflections on all sides, and, therefore, should be flat, 

 or nearly so, excepting at the angles, which should be 

 curved or hollowed. From the orchestra the sound is 

 chiefly required to be projected forward as from the singers 

 mouth; and, therefore, an orchestra should have curved 

 walls and roof. 



Space will not permit a dissertation here on the particu- 

 lar curv,3 required. This has, I believe, been carefully 

 calculated in constructing the Crystal Palace orchestra. 

 Viewed from a distance, the whole orchestra is curiously 

 like a huge wide-opened mouth that only requires to close 



