HISTORY IN TOOLS PKTEIE. 



567 



In other cases we can trace the gradual evolution of a tool down 

 to the present day. The carpenter's saw was at first merely a blade 

 roughly hacked on the edge; by 4,500 B. C. it had regular teeth, 

 sloping equally both ways; by 900 B. C. the Italian gave a rake to 

 the teeth to make them really cut in one direction, instead of merely 

 scraping as before. No ancient saw, however, had a kerf, cutting 

 a wider slit than the thickness of the blade; we do not know when 

 that was invented in the Middle Ages. The Egyptian used a push 



9 to 14. — Bronze Age inventions of Italy; not used hy Egyptians. 

 15 to 19.— Forms not used by Egyptians. 



saw as the earliest form ; the pull saw was the only one in the West 

 and the Roman world ; the push saw came back into use in the last 

 few centuries, though the pull saw in a frame is still universal in 

 the East. The world did without shears for many ages, cloth being 

 cut with a rounded-blade knife (fig. 34). About 400 B. C. the 

 mechanical genius of Italy invented the shears, which in two or three 

 centuries more were fitted to the fingers, and thus started the scissors. 

 The snuffers in Exodus is a mistranslation ; the early tools for trim- 



