Wyborn's "Notes for Architects and Draughtsmen" gives the following rules for the proper proportions for a building in order that speaking from platform or pulpit may be distinctly heard all over the room. For concert rooms, etc., height 2, width 3, length 1 or 5. Example: - Free Trade Hall, Manchester; height 52 ft., width 78 ft., length 135 ft. For lecture rooms, etc., height 2, width 4, length 3. Example: - Theatre of Royal Institution; height 30ft., width 60 ft., length 15 ft. The hearers should not be at a greater distance from the speaker, for convenient hearing, than 50ft. in front, 30ft. on each side, and 20 ft. behind. No person should be farther than 70 ft. from the speaker. The greatest number that can hear a speaker conveniently is 2,000, arranged in two tiers. The end opposite the orchestra or speaker should be semicircular, or have the angles rounded. The ceiling should be elliptical or coved, and there should be a hollow space beneath the floor.