64 THE LESSON OF EVOLUTION 



received iron vessels as tribute from Syria. It was 

 known to Homer, but evidently it was not common 

 in his day. From these facts it is customary to 

 divide the early history of man into three ages, 

 called respectively the Stone age, the Bronze age, 

 and the Iron age, according to the nature of the 

 material from which he manufactured his weapons. 

 But these ages overlap ; both bronze and iron were 

 introduced into southern Europe first, and their use 

 spread northwards slowly, gradually displacing the 

 inferior materials. Thus about B.C. 1000 to 500 a 

 Bronze age existed in central Europe, while a Stone 

 age existed to the north, and an Iron age had com- 

 menced in the south. Brass came later than iron, 

 and was obtained only by smelting copper ores which 

 contained " cadmia " or zinc. It was used in 

 Europe during the Roman Empire, but did not be- 

 come common until the sixteenth century, when the 

 art of making zinc was discovered. 



Gold , as well as copper and bronze , was used from 

 a very early date for ornaments ; and throughout the 

 Bronze age flint arrow-heads continued to be used. 

 Silver did not come into use until the Iron age. 



Pottery was made in the later Stone age, and at 

 first was only sun-dried. 



Glazed earthenware is first known from Egypt 

 (about B.C. 1200) as well as a kind of porcelain ; 

 but true porcelain is an invention of the Koreans, 

 and was introduced from China into Europe at the 

 close of the 15th century. 



The art of making glass appears to have been dis- 

 covered by the ancient Egyptians, as it was known 



