ELEMENTS, COMPOUNDS, AND MIXTURES 251 



are seen only in the laboratory. Each metal is different 

 from the others in certain characteristic properties. 

 Metals have their own special properties which enable 

 us to distinguish them as a class quite readily. For ex- 

 ample, metals may be melted, fusibility ; they conduct 



Copyright, 1915, by Keystone View Company. 

 FIG. 222. Surface Mining, Mesaba Range, Minnesota.. 



heat and electricity, conductivity ; they may be ham- 

 mered into thin sheets, malleability ; tad the fresh sur- 

 faces of metals have a peculiar luster,.' , 



Iron. Iron is the most important of all the metals. 

 It is found in a number of ores and is sometimes found 

 in a free state in igneous rocks. Its abundance and its 



