1869.] On Warming and Ventilation. 721 churches of Europe, were built in con- formity with the religious forms and usages of Catholic countries. The Catholic cathedrals are open every day for worship. They are furnished with but few seats ; for the worshippers, remaining but a few devout minutes, are constantly passing in and out ; hence they require but little warmth. Our people, on the contrary at least the Protestant portion of them, enter the churches, and remain seated for hours ; and if in Gothic or Byzantine buildings, the}' suffer dreadfully, either in their pockets or in their bones. The most commonly adopted method, of heating our public buildings at this day, is by hot air. Now what is more beyond human control than air, in its movements ? and as regards ventilation, what so little understood, and in general so ill managed ? and what so essential to our health and comfort ? Long dissertations are laid before the public, explaining, or attempting to explain, the theory of ventilation and of respiration, with its exhaustion of oxygen gas from the air, and exhala- tion of noxious gases, and consequent deterioration of the atmosphere, in a crowded apartment. We have in some buildings, ventilating shafts or flues built for the purpose of carrying off the foul air. But do not pure air and foul air go out of these flues in company ? Certainly they do. Can the skill of man prevent it ? Certainly it cannot. With this system of warming ajjart- ments, all the air must be in perpetual motion, fresh air coming in and mixed air going out; and the question arises, whether this movement of air (even warm air) over the persons of those occup3 r ing the room being thus heated, and ventilated, is not productive of colds and rheumatisms? We all know, that air which is sta- tionary, now becomes oppressive ; the explanation of this is that remaining dormant in contact with the person it forms a sort of coating, and air being a bad conductor of heat, prevents the heat of the body from freely escaping. The use of a fan, is a relief, by driving off the heated coating, and suppling fresh air in its place. The air is not cooled by the fan, but changed. This duration of coolness is in part due to the evaporation of the moisture from the surface, caused b} r the motion, but to a greater extent by the removal of hot air. Thus it is in a room with hot air rushing through it in search of the ven- tilating shaft, and every one in the room is liable to be affected by it in an injurious manner. The points to be gained, are: 1st. The introduction of fresh air, heated in such a manner as to be imperceptible to the occupants of the room. 2d. Its introduction in such a manner, that it cannot be vitiated by passing over the persons of those who may be disposed to stand over and around its place of entrance. The first may be avoided, by intro- ducing the air, not in a current, like a sirocco; but so equally diffused that every portion of the space to be venti- lated and heated may receive its share. As to the second point, it is hard to understand, how it is, that so little notice is taken by engineers and archi- tects, of the impurities, disgusting as they are, which are sent flying into our public rooms, from the hot air flues. We have our heaters so arranged, in most cases, so as to supply our apart- ments with the most pestiferous air, while we at the same time build ventila- ting flues to carry off this same foul air. Go into the auditoriums of our public buildings, or churches, our court rooms, and lecture rooms ; and into most of them, hot air is introduced through large openings, covered by gratings in the floors of the aisles. On a cold day crowds gather on these hot air vestibules. Some spit tobacco juice into them, some scrape off from their boots, the dirt}- snow ; others heat
