BURNING OR OXIDATION 



of oxygen. This gas is the most widely distributed gaseous 

 compound of the entire world ; it is found in the ocean depths 

 and on the mountain heights, in brilliantly lighted rooms, 

 and most abundantly in manufacturing towns where factory 

 chimneys constantly pour forth hot gases and smoke. 



Wood and coal, and in fact all animal and vegetable matter, 

 contain carbon, and when these substances burn or decay, the 

 carbon in them unites with oxygen and forms carbon dioxide. 



The food which we eat is either animal or vegetable, and 

 it is made ready for bodily use by a slow oxidizing process 

 within the body. Carbon dioxide accompanies this bodily 

 burning of food just as it accompanies the fires with which 

 we are more familiar. The carbon dioxide thus produced 

 within the body escapes into the atmosphere with the breath. 

 The source of carbon dioxide is practically inexhaustible, 



coming as it does from 

 stove, furnace, and 

 candle, and from every 

 breath of a living or- 

 ganism. 



Ventilation. - - Where 

 many people are gathered 

 together in badly ven- 

 tilated rooms, the air 

 soon becomes foul and 

 causes headache and 

 weariness, This dis- 

 comfort is due less to 

 carbon dioxide than to 



FIG. 28. -Removing bad air from a room. hi g h temperature, high 



humidity (see page 43) 



and disagreeable odors from hot perspiring bodies and soiled 

 clotheso 



