WARMING AND VENTILATION. 277 



to a comfortable tlegTee. The additional fresh-air ducts would thcu be 

 ofton found unnecessary, and might be closed. 



The amount of air brought into the room through the openings in the 

 ceiling was found the same day, February 7, to be equal to 60,000 cubic 

 feet an hour, confirming the jjrevious opinion. 



The amount of foul air carried off by the ventilating-chimney was as 

 much as 05,000 cubic feet the same day and under the same circum- 

 stances. The mean temperature in the chimney was — 



February 6 84^ 



That of the external air being 41^ 



Difference 40^ 



Thus, with this meau winter-temperature, that of 01° was maintained 

 in the room, and, with an excess of 40° in the chimney over that of the 

 air, almost 03,000 cubic feet of foul air was carried off", as has been 

 stated. 



The consumption of fuel an hour was — 



Pounds. 



For heating 7 



For the ventilating-chimney 3 



10 



The babies being left in the morning and taken away by their mothers 



in the evening, it will be sufficient, in ordinary weather, if the fires be 



kept up at most eiglit hours a day. The daily consumption will then be 



on a mean 10x8=80 pounds a day. 



The fuel used is composed of 75 per cent, of coke and 25 per cent, of 

 coal, and it will be estimating it above its value to charge it at $10 a 

 ton. The expense of fuel during the winter would then be at most 



,^. -—36 cents a day, or 836 for 100 days, to obtain a change of air at 



the rate of 63,000 cubic feet an hour. 



During the season when artificial heat is notrequired, the ventilating-fire 



alone should be used, and will usually burn not more than about SJpounds 



of coal an hour, or 27 lbs. a day, for the period when the opening of windows 



200x27x10 

 will not be sufficient, or during 200 days, ^J^JIi] ^ = $24. The total 



annual expense would then be at most $00 for an asylum which, though 

 intended for but 50 children, might easily receive 100 in the large well- 

 ventilated apartment, which has a content of 23,000 cubic feet, giving, 

 in that case, 230 cubic feet for each child ; while in the primary schools 

 of Paris there is allowed, on an average, but about 155 cubic feet to each 

 child of from to 12 years of age. 



Under these conditions, the ventilation of 63,000 cubic feet for 100 

 beds, or 230 feet a bed, an hour would be almost double what is neces- 

 sary, and could easily be reduced to 42,000 cubic feet an hour. But even 

 supposing that it be kept as it is, the mean expense for each child would 

 be at most 60 cents a year. 



