86 Ventilation with Heating. 



we take a room such as this and heat it with an ordinary stove, 

 we shall get in all parts of it a mixture of foul air of nearly- 

 equal impurity ; and without an excessive consumption of fuel 

 for heating purposes, which admits of an excessive amount of 

 ventilation in the ordinary way, such as openings in the ceiling 

 for exit and openings near the floor for inlets, this mixture after 

 the first half hour can never be anything else than very im- 

 pure. It will also be difficult to avoid cold drafts on the 

 audience from the inlets, while an outlet at the floor does not 

 cause a perceptible draft three feet from the opening. Since 

 the winter has passed, it has been found for summer ventilation 

 that fresh air can be admitted near the ceiling, and foul air 

 extracted at the floor, producing good ventilation without dis- 

 comfort ; but this cannot be effected without force to propel 

 the air. 



In reply to Mr. Gray, vitiated air and pure air tend to mix, 

 but the mixing takes time. The method advocated in this 

 paper is intended as far as possible to avoid this mixing. There 

 should probably in most cases be two distinct systems of 

 ventilation, one when artificial heat is required, and another 

 when it is not required. 



In reply to the Rev. Mr. Workman, if the building is heated 

 by warmed/Mr<? air^ it will ascend and accumulate above, leaving 

 the impure air below. The only way to bring down the pure 

 warm air in this case is to draw off the foul air near the floor 

 level. The effect produced by lowering the pulpit was to in- 

 crease the capacity of the store of foul air above, carried up by 

 the heat of the burning gas and charged with carbonic acid 

 from its flame, giving a longer time before its bad effects were 

 felt at the now lower level. 



The President asked if there was any advantage in the 

 Sirocco Stove. Its outer casing makes it possible without 

 alteration to employ it for drawing in fresh air and heating it. 

 It also produces a large quantity of warm air in a most econo- 

 mical manner. The testing of the Sirocco Stove gives 90 per 

 cent, of the total heat produced by the coal in the air heated. 



