Ventilation with Heating. 73 



group of gas jets, and filled with air at a temperature of two to 

 four hundred degrees. But the difficulty in ventilation does 

 not arise from the want of means of drawing away foul air, or 

 of driving in fresh air. It comes from quite a different cause, 

 which, when traced to its source, is hidden in the three letters 

 i s. d. 



Our usual means of producing heat are too slow and wasteful 

 in their operation of warming a sufficient quantity of air, to 

 make ventilation, as usually carried out, anything more than a 

 mere excuse. With such sources of heat as these no audience 

 would endure the amount of ventilation required for health. 

 Take any of our public buildings in which people assemble, 

 ventilated as they are at this time of the year, allowing it to be 

 no more than three-fourths full. Provide this assembly with all 

 the necessaries of life, how many would be painfully ill in 24 

 hours ? How many, inside a week, would have to be carried out 

 dead ? Release the survivors, if any, at the end of a fortnight, 

 how many of these would be fatally striken with consumption, 

 fever, and other diseases ? The experiment dare not be tried 

 on human beings, but the results may be guessed from what has 

 been tried on animals. How often do we find consumptives 

 trace the commencement of their illness to a cold, caught at a 

 dance, a concert, or a church, according to their respective 

 tastes, whose illness would have been only a cold, and nothing 

 more, if it had not been for the poisoned air inhaled 1 



The ordinary method of ventilation is to have a few openings 

 in the ceiling to carry away the hot foul air. Some of these 

 ventilators may do this in an indolent way, like workers paid 

 by time when their foreman's back is turned, while others are 

 mischeviously taking delight in pouring a stream of cold air 

 on the heads of venerable persons, whom age has deprived of 

 their proper protection. Another method is to provide a few 

 openings in the lower part of the building to admit fresh air. 

 The third and more perfect method is to combine these two, 

 and have openings both of admission and of exit. The first 

 methods being plainly defective, as air cannot be drawn from 



