136 Mr Russell on the Conslruclion of Buildings. 



theatre may be satisfactorily determined. Let A be the place 

 of a figure on the proscenium, and the lines o, 6, f, and (/, the 



Fig. 5. 



vertical elevations of individuals in different parts of the house 

 above the intercepted ray from A : then these being made every 

 where equal, all parties see and hear without interruption. The 

 evils arising from reflection of the voice from walls, and the evil 

 of echoes, would be removed, if, by the elevation given to tlic 

 hinder seats on this principle, the great proportion of the house- 

 walls of the building were covered with auditors, and the sphere 

 of sound and sight almost wholly occupied in useful effect. 



For any great assemblage where it is desirable that one indi- 

 vidual or group of individuals should be seen or heard, an am- 

 phitheatre of this form might be constructed from the surface 

 of revolution, generated by moving the curve round its axis, 

 which would perfectly accommodate 10,000 individuals. We 

 have given, see Plates I. and II., a sketch of the interior of a lec- 

 ture-room, of a church, or music-room, in which the auditors 

 are placed in the isacoustic curve. The intelligent practical 

 architect will readily see the method of carrying these arrange- 

 ments into effect in other circumstances. 



