Air ivithin an Auditorium upon its Acoustic Qualities, 115 



is amply sufficient for ventilation is shown by the fact that the 

 thermometers of the upper circle do not vary perceptibly from 

 those of the orchestra circle. 



The seating-capacity of the house is about sixteen hundred 

 persons. The acoustics are, if we may judge from the testi- 

 mony of a large number of singers and speakers, as well as 

 from our own observation, among the best. 



The weakest voice is audible to every seat in the house ; 

 sounds such as a sigh, a kiss, or even the simulated breathing 

 of the somnambulist, may be heard in the most distant parts ; 

 and all effects in music are exactly rendered. Allsingers and 

 speakers agree in describing the facility with which the voice 

 is used on this stage. 



It now remains to show that the universally acknowedged 

 acoustics of this house are largely due to the condition of the 

 air, and not to the arrangement and material of the walls, 

 together with other well-known causes of success or defect. 

 For this purpose persons have been repeatedly stationed at 

 different parts of the house during a performance, without 

 being informed of the nature of the experiments to be carried 

 out. They have simply been asked to note, at intervals during 

 the evening, the comparative ease with which they could hear 

 the performers. At various intervals during the evening the 

 valves which control the ventilation were reversed, so as to en- 

 tirely interfere with the unbroken condition of the air and give 

 rise to currents of circulation. Almost invariably the testi- 

 mony of the hearers would be that, at times corresponding to 

 the interruption of the ventilation, the " sound was dead," was 

 "confused and indistinct;" and it would be observed that 

 people all over the house would make an effort to listen. As 

 an example of these experiments, the following is copied from 

 the author's notes, for the evening of January 24, 1878. 



There was a concert, consisting of orchestral music and solos 

 held in the house. At 8 o'clock observers, A, B, C, and D, were 

 stationed respectively in the orchestra, right and left wings of 

 the balcony, and on the bridge that spans the stage above the 

 level of the highest proscenium boxes. They were entirely 

 ignorant of the nature of the experiment, and were simply re- 

 quested to note the times of good and bad hearing. 



At half-past eight o'clock the valves were reversed and 

 remained so till nine, when they were again set aright ; after 

 the performance the following testimony was given by the 

 different observers : — 



A. Orchestra — to 9.15, very indistinct; 9.15 to 10, much 

 better. 



