26 JOURNAL AND PROCEEDINGS 



raise 480 cubic feet of air one degree. The heat necessary to 

 change a gallon of water from the freezing point to the 

 boiling point would raise 86,400 cubic feet of air one degree 

 or 2000 cubic feet from the ordinary winter temperature of 20° 

 to 65°, the temperature of occupied rooms. If the heat is 

 properly managed it is not so expensive as some people 

 imagine, and will be found much cheaper than medicine. 



When heated, air expands 1-500 for every degree, and 

 when heated from 20° to 70° expands 50 x 1-500 or i-io, and 

 heated still higher expands still more. This lessens the 

 weight of equal volumes of air and is the cause of the drafts 

 in the chimneys. 



To test for carbon dioxide pass a quantity of air through 

 lime-water, when it will turn milky if carbon dioxide is 

 present; or shallow saucers containing lime-water may be 

 exposed in the room, when a film will be formed on the surface. 



To test for organic matter pass the air through sulphuric 

 acid, when its presence will be shown by the acid turning a 

 dark color. 



The test for Ammonia is known as Nessler's test, and 

 would require considerable quantities of air. Ammonia is the 

 great supporter of microscopic organization, and is produced 

 by the decay of animal and vegetable matter. 



