WARMING AND VENTILATION. 305 



of which cannot be increased much beyond its normal rate, it will be 

 advisable to phice gas-burners in the main ventilating-chimney, to be 

 lighted only when a temporary overcrowding or the fear of epidemics 

 renders tlieir use necessary. 



The number of burners and their consumption of gas will be calcu- 

 lated on the approximate basis of 500 cubic feet of air removed to each 

 cubic feet of gas burned. 



This auxiliary means is not economical, and should only be employed 

 in exceptional circumstances. 



AsVlums. 



95, Asylums, designed for the old, insane, or infirm, do not require, 

 for salubrity, as much ventilation as hospitals. 



A renewal of air at the rate of 1,000 cubic feet of air an hour for 

 each individual during the day and 1,400 cubic feet at night will be 

 sufficient. It will then only be necessary to adopt the plans and the 

 dimensions which have been given in detail for hospitals. 



For heating during the winter, if the rooms are not very large, venti- 

 lating fire-places should be used, which will also secure the renewal of 

 air. But for spring, summer, and autumn, it will be necessary to have 

 recourse, for the removal of foul air, to the use of a ventilating-chimney 

 and the arrangements before mentioned. 



CHURCHES. 



96. The great size of churches, the constant opening of their doors, 

 the extent of glazed windows — always imperfectly closed — the openings 

 in the vaults for the suspension of lamps or draperies and foi- the pass- 

 age of bell-ropes, seem in general to render unnecessary the adoption 

 of special arrangements for the admission and the removal of air, and 

 reduce for the winter the question to that of warming. 



For the churches of large cities, frequented at many hours of the day, 

 it seems economical to keep up an active fire, constantly, day and night. 

 Either hot-air heaters, with chambers for the admission of cold air, or 

 hot-water heaters, may be used. The first suit more particularly the 

 small churches, where a single heater, placed about the middle of the 

 building, will suffice. The second, which carry heat to great distances, 

 and give, besides, a more equable temperature, should be preferred for 

 large churches. They have, in addition, the advantage of being readily 

 adapted to ventilate certain attached places, such as catechisiug-rooras, 

 where the air is constantly vitiated by the presence of many children. 



What is most necessary to warm in churches is the floor itself. For 

 this purpose it would be well to make the hot-water pipes branch out 

 under many parts of the floor, and limit the number of fresh-air openings. 

 This arrangement is similar to that of which traces are found in Roman 

 constructions. 

 20 s 



