PROCEEDINGS OP THE POLYTECHNIC ASSOCIATION. 587 



ations become deeper and less frequent; he experiences, in the course of a 

 short time, an agreeable glow in his chest, as if the pulmonary cells were 

 becoming dilated with an elastic spirit, while the whole frame receives at 

 each inspiration a fresh vital impulse. The functions of the brain get 

 excited, the imagination becomes vivid, and the ideas flow with a delightful 

 facility, digestion becomes more active, as after gentle exercise in the air, 

 because the secreting organs participate immediately in the increased 

 energy of the arterial system." 



The habit of excluding fresh air is fostered by the craving for warmth, 

 and the deficiency of our heating appliances to keep up the necessary 

 warmth, allowing a free circulation of fresh air. 



As fuel to the poor is a very expensive item, it is not to be expected that 

 they would sacrifice heat for ventilation, of the necessity of which they are 

 mostly ignorant, but it is to be hoped that the necessity for the building of 

 model houses for the poor and working classes will in time be found out 

 when they may enjoy the luxury of fresh air with the exclusion of cold in 

 addition to cleanliness, pure water and light. 



If compressed air were furnished us as gas and water now are, there 

 could be nothing simpler than the heating of our dwellings by heating the 

 compressed air in a furnace in the cellar to any temperature required and 

 then passing it through pipes surrounded by the products of combustion to 

 retain the temperature required. The air bypassing through the registers 

 into the room would heat it equally, being under pressure and without the 

 possibility <jf local draft, at the same time giving a delightful freshness 

 and elasticity to the atmosphere, resembling that of the open, calm air. 

 In this way whole blocks of buildings might be heated by one or more 

 furnaces specially constructed and attended by one person, saving im- 

 mensely in fuel as well as in care and cleanliness. But above all, in sum- 

 mer, when the thermometer indicates a temperature often exceeding 100 

 degrees, the pure atmospheric air, cooled by passing from some elevated 

 suburban spot through pipes lain in the ground, would so much reduce 

 the temperature of our rooms, our schools, churches and hospitals, as 

 would preclude the necessity of sending our families into the country or to 

 sea shore watering places. 



Light, another necessity, also depends on compressed air; it requires 

 ten cubic feet, of pure atmospheric air to supply two cubic feet of oxygen, 

 to effect the combustion of one cubic foot of coal gas; but if the air does 

 not contain the two cubic feet of ox3^gen for ten feet, part of the gas must 

 pass ofl" unconsumed. Also by taking heated compressed" air through 

 hydro-carbon, a good light can be obtained at a much lower price than is 

 charged by gas monopolies. In short, compressed air, when once intro- 

 duced, will be used for an endless variety of purposes besides those named 

 above, as for melting and soldering where the blow-pipe is used, for boil- 

 ing and cooking with common^gas, for drying purposes, in laundries, 

 dyers' works, cloth, paper, hall oil cloth, India rubber works, carriage man- 

 ufacturers, chemical works, cabinet makers, and many others. 



The greatest and most enduring monuments that men haVe erected to 

 perpetuate their names, are the great water-works which supply large 

 cities with this necessary element. But he who will supply our large 



