THE BEGINNINGS OF KNOWLEDGE 5 



it again and found by bitter experience that round 

 smooth stones retarded his operations. Still later 

 some man may have broken a stone by throwing it 

 against a rock, hoping to find among the pieces one 

 suited to his needs. 



In some such way there developed the idea of using 

 tools and of forming them. Of course, it is only a 

 small step from breaking the stone as just described 

 and chipping off edges of the selected stone so as to 

 form it more nearly to the desired shape. But this 

 step may not have been taken for centuries. Even 

 if some man did make this advance and his tribe learned 

 it from him, accident or disease could have destroyed 

 them all and with them the precious knowledge. There 

 were as yet no records of past achievements to save a 

 student the mistakes and trials through which ages 

 of mankind accumulated and arranged its knowledge 

 of the physical world. 



If food became scarce in the region where lived a tribal 

 group which had learned to preserve fire it may have 

 wandered into other regions and so spread its special 

 knowledge. This change from the old conditions and 

 the necessity of meeting new ones would have stimu- 

 lated it to new discoveries along other lines, as perhaps 

 in the making of vessels for carrying fire and water on 

 its travels. In this migration it may have met another 

 tribe with other knowledge. If they fought the weaker 

 tribe perished with its knowledge, or if they mingled 

 the enlarged group enjoyed the knowledge common to 

 its parts. 



Except when tribes amalgamated the exchange of 

 information must have been very slow because of the 



