PREHISTORIC PERIOD. 



By the late B. C. POLKINGHORNE, B.Sc., F.C.S., 

 Lecturer in Chemistry and Geology, Woolwich Polytechnic. 



It does not require a great effort of imagination to conceive a 

 time when man was in so primitive a state that his implements of 

 war and peace were confined to stout cudgels and unfashioned 

 stones. The former, through lapse of time how long it is perhaps 

 too rash to suggest, though competent archaeologists do not 

 hesitate to ascribe an antiquity of 200,000 years to mankind have 

 necessarily perished, and the latter could not be identified. But 

 when accident or random movement suggested to the mind of the 

 primeval savage that, by knocking one stone against another, a 

 cutting instrument was possible, rapid progress in the fabrication 

 of such weapons must surely have taken place. Certain it is that 

 man, contemporary in this country with the mammoth rhinoceros, 

 cave bear, and other extinct mammals, was not the uncouth 

 creature he is sometimes supposed to have been. His implements 

 show great manual dexterity and a purposiveness frequently 

 apparent even now. And when the raw material available for his 

 arts was chalk flint, he speedily found that serviceable pointed and 

 edged tools could be fashioned for operations of boring, cutting 

 and chopping. In districts where chalk flint was not to be found 

 native, other material, such as chert (possessing the same 

 properties as flint in a less favourable degree) and obsidian (a 

 natural glass) were used instead. 



The property of flint, making it so adaptable for fabrication of 

 tools, is that which is described as its " conchoidal fracture." A 

 suitable nodule of flint struck with sufficient force near the edge of 

 a convenient face by another pointed piece of flint a pebble 

 would also serve detaches a thin " flake." A " flake " usually 

 shows a " point of percussion," and, spreading from this, a fresh 

 convex surface which can be refitted into a concave " flake hollow " 

 in the residual " core." The beginning of the conchoide is a part 

 of a cone it is known as the " bulb," and corresponds with a 

 bulb-hollow on the core. The margin of such a flake often exhibits 

 a sharp edge quite capable of use as a cutting instrument without 

 further work. Usually, however, it was made more useful and 

 permanent by further elaboration. ' 



