Veniilanon with Heating. 81 



would have a tolerably high temperature to help it, but would 

 be retarded by friction in passing through the fuel. It would be 

 hard to estimate the amount of air escaping through the seams of 

 the boarded ceiling, but for the purposes of ventilation that may 

 be neglected, for what would escape there would be pure un- 

 respired air, as explained before. From this we may fairly 

 estimate that a comfortably pure atmosphere was maintained in 

 the school for some four hours. It was comfortable, that is not 

 oppressive, at the end of that time, with a change of air of only 

 215 feet per head per hour. We may take it for granted that 

 nearly all the air entering the room passed through the stove 

 and was heated there. The action of the stove would tend to 

 produce a slight elevation of the pressure inside the building 

 compared with that outside, consequently air would not tend to 

 come into the building excepting through the stove. It was 

 hardly possible to measure the quantity of air passing through 

 the stove, the opening being about two feet long by one foot 

 broad, and there was not an even draft over the whole area. 

 There was no available means of contracting the orifice to cause 

 an even flow. There would be more than 20,000 cubic feet of 

 air passing through the stove per hour, but rather less than 

 this was available for respiration. 



The Siemens's Lamp in the lecture room of the Soldiers' 

 Home consumes 40 feet of gas per hour. If the products of com- 

 bustion of this were allowed to pass into the room, as is usually 

 done, they would add to the carbonic acid present as much as 

 43 men would produce in the same time. The room will seat 

 about 220 persons. Suppose it were shut up closely, it would 

 only contain air enough to form a healthy atmosphere for six 

 men for one hour. This seems to show that money would be 

 better spent in supplying well-warmed pure air, than in 

 large buildings with the hope of making them airy because of 

 their size. If the upper third of some of our public buildings 

 had been left unbuilt, it would have saved a sum of money 

 sufficient to have endowed them for ever with warmth and 

 ventilation in abundance, and probably have left sufficient to 

 endow for the most luxurious lighting also. 



