CHAPTER VIII 

 CARBON DIOXIDE 



39. Carbon and its Forms. Carbon is a simple sub- 

 stance or element composed of simple molecules. It 

 exists in forms varying from powdered charcoal to the 

 hard crystallized form known as diamond. It enters 



Crystal Rough 



DIAMONDS. A FORM OF CARBON 



into the composition of all plants and animals, being one 

 of the most important elements. Our bodies the bones 

 and flesh are partly carbon, and the smallest microscopic 

 animals contain carbon. A large percentage of the plants 

 around us, such as the grass, flowers, vegetables, and 

 trees contain carbon. It is in the wood, oil, coal, and gas 

 that we burn, in the clothes we wear, in the food we eat. 

 We are kept warm by the oxidation of the carbon in the 

 food we eat. Buildings are heated by oxidizing the car- 

 bon in the fuel. 



Charcoal is one of the commercial forms of almost pure 

 carbon, and it has many uses other than for fuel. Some is 

 used in the reduction of ores and purification of metals. 



