318 WARMING AND VENTILATION. 



It would then be necessary to admit into, and discharge from, the 

 room every hour the amount ot^ — 



;.:!■,.. =1,268,000 cubic feet, 



or 352 cubic feet a second, which corresponds to a complete renewal of 

 the air of the room effected 14.27 times an hour. If the velocity of dis- 

 charge reaches GJ feet a second, the total sectional area of the openings 

 should be 54 square feet. 



The amount, 1,268,000 cubic feet, is about that which can easily be 

 withdrawn from the lecture-rooms of the Conservatory, and introduced 

 there at a mean height of less than 20 feet without inconvenience to 

 the audience. 



116. Dining-room. — This room has the following dimensions : length, 

 49 feet ; breadth, 23 feet ; height, 25 feet ; cubical capacity, 28,000 cubic 

 feet ; floor-surface, 1,120 square feet. 



It accommodates 54 guests at a table 42 feet long by 10 feet wide, hav- 

 ing therefore a circumference of 104 feet, and giving to each guest but 2 

 feet of table-space. 



The number of servants is about 14. There are then 68 persons in 

 the room. 



The cubical space for each person is — 



28000 ._^ T f . 

 P^ =410 cubic feet. 



The floor-surface to each person is — 



1120 

 ..^ =16 square feet. 



It is lit up by — 



1 chandelier -. 60 candles, 



14 chandeliers of 20 candles each 280 candles. 



Portable candelabras 170 candles. 



Total 510 candles, 



or 9.44 candles to a guest. 



Admitting the same bases of calculation as before, the total number of 

 units of heat developed in an hour by the people and the candles will be 



(68+510) X 476=275,128 units, 

 and the amount of air to be admitted and withdrawn every hour would 

 be— 



' ..7. =421,000 cubic feet, 



or 117 cubic feet a second, which corresponds to a complete renewal of 

 the air of the room effected 15.23 times an hour. 



The amount, 421,000 cubic feet, is less than t-hat which is constantly 

 admitted into and withdrawn from the small lecture-room at the Con- 

 servatory. 



Under the arrangements at present in use, it is not uncommon to find 

 at the close of a meal a temperature of S6^ without any change of air, 



