Proceedings of tee P olttechnic Association. 897 



air flows out continually. Another great advantage gained by this 

 plan is the equality of the temperature of the air. Actual experi- 

 ment shows that there is not more than five degrees Fahrenheit 

 diiference between the temperatui;e at the ceiling and at the floor ; 

 while in a room warmed by a stove, the difference is from twenty to 

 forty-five degrees Fahrenheit. 



This plan of passing the foul air out, at or near the floor, is emj)tiati- 

 cally new. It is an idea which has completely revolutionized the 

 old systems of ventilation. The purest and warmest air is always at 

 the top of the room ; while the coldest and most impure is always at 

 the bottom. If we make an opening at the top of the room, the 

 purest and warmest air will escape; if at the bottom, the coldest and 

 most impure ail' will escape. It would seem that it is not difiicult to 

 determine which of these two plans is the sensible or true one. It 

 scarcely seems necessary to claim more for this system. If pure air 

 is so absolutely essential to physical well-being, and if we can adopt 

 any means, however expensive, to secure it we might rest satisfied. 

 But it is far from being expensive ; while on the contrary, a build- 

 ing, whether large or small, can be constructed as cheaply with such 

 provision for ventilation as without it ; and can be warmed at much 

 less expense than by any other plan. The cost as compared with 

 that of heating by steam is less than one-third, as I have clearly 

 demonstrated by a series of careful experiments and observations. 

 As compared with ordinary hot air furnaces, not more than one-half. 

 As compared with ordinary stoves, it is decidedly less. In short, 

 this system seems to possess every possible advantage. It is simpler, 

 cheaper, and, best of all, it gives what is so much needed — a full, 

 complete, and constant supply of pure air ; and I honestly believe 

 that when this system is generally adopted in our country, the rates 

 of mortality will indicate a marked decrease. 



Considerable discussion followed, from which it was apparent that 

 many were of opinion that while the Ruttan system would work 

 admirably in very cold weather it was doubtful whether it could be 

 made to operate well under all -changes of temperature. 



Adjourned. 



[Inst.J 57 



