MAN'S PROGRESS: GROWTH IN RELIGION 



After men had learned the use of metals they 

 progressed much more rapidly, not only in the arts of 

 building and in making articles for household com- 

 fort, but in knowledge of the world and the treasures 

 for their use that it contained. Once having learned 

 how to use the metals, they could not do without 

 them. When their supply was used up they were 

 obliged to search for more. 



That meant that they must go about, travel to 

 other places, visiting other tribes and exchanging 

 goods with other people. This was commerce, and 

 commerce, even on so small a scale as that, is a great 

 civilizer. The very need of going about makes it 

 necessary for new methods of travel to be invented. 

 Besides, people who trade with one another learn 

 from each other better ways of living and working. 

 So the discovery of metal helped them in these two 

 ways, by the better implements that they were able 

 to make with it, and by the need to go about to get 

 new supplies. 



At first, of course, men traveled only on their own 

 feet. They did not need any help, for they were 

 strong and fleet of foot, and they did not go long dis- 

 tances from their caves or their fires. When need 

 arose, they would carry their burdens on their backs, 

 or upon their heads, or in their arms. But when the 



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