112 



CARBON AND ITS COMPOUNDS 



FIG. 92. 



Making Charcoal from Wood. Burning part 



of the wood gives off the heat necessary 



to char the remainder. 



of uses by man. Charcoal made from wood and bones is 

 very porous, and the air in its pores is able to destroy 

 (oxidize) many natural coloring materials, as well as gases 



and bacteria. Charcoal 

 (Fig. 92) is, therefore, 

 used to take the color out 

 of sugar solution and 

 vinegar, as a disinfectant 

 (cf. 110), and as a ma- 

 terial for filters (cf. 84) . 

 Soot, or lampblack, is 

 used to make printer's 

 ink, black paint, etc. 

 Gas carbon (cf. 124) is 

 used for the carbon " pencils" of electric arc lamps and 

 for the plates of electric batteries (cf. 150). The 

 diamond is used not only as a jewel, but also as a 

 cutting and polishing material. It is the hardest substance 

 known. Graphite is used for lead pencils, as stove polish, 

 and to destroy "boiler scale" (cf. 82). 



Charcoal, coal, and coke are used as fuels, and to reduce the ores 

 of iron and other metals (Fig. 93). Most of the metals are found as 

 oxides (cf. 48), or as compounds that can be changed easily into 

 oxides. When the oxide of the metal is heated with carbon, the carbon 

 unites with the oxygen, releasing the metal. We say that the ore is 

 reduced by the carbon. Copper, tin, lead, zinc, etc., are obtained in 

 this way. The commercial apparatus for reducing the ores of iron is 

 called a "blast furnace" (Fig. 94). 



120. Hydrocarbons. There are thousands of sub- 

 stances consisting of carbon combined with other ele- 

 ments. Carbon compounds are also called organic com- 



