564 The Museum Gazette 



OUR LEXICON PAGE.— EXPLANATION OF 

 SCIENTIFIC TERMS. 



{Continued from p. 510.) 



The Age of Copper. — There is little doubt that copper 

 was the metal which was earliest made use of by mankind. 

 Its softness, however, was a great disadvantage, and as it was 

 soon found that it could be made harder by mixing a little tin, 

 bronze quickly superseded it. There is, then, no period of 

 time which should be known as "the Copper age," and few 

 tools made of pure copper have survived for our museums. 

 For coins it came early into use, and, as most know, it is so 

 still. 



The Stone Age. — These immense periods of time comprise 

 all the early stages of human civilisation during which stone 

 implements were the only ones in use, and the metals were 

 unknown. For a large part of the world the stone ages came 

 to an end gradually about four thousand years ago, stone 

 being superseded by bronze and iron. Some isolated races 

 are, however, still in the stone stage. Stone tools were never 

 in exclusive use, having always been helped out by those of 

 wood, bone, teeth, shells, &c. The stone ages have been 

 divided into three stages in reference to the amount of skill dis- 

 played in fashioning the implements. Eolithic are those of 

 extreme antiquity, which show the least possible traces of 

 human preparation. Paleolithic, those which are formed, 

 and to some extent chipped, but not ground or even finely 

 chipped. Lastly, Neolithic are those ground or chipped to 

 fine edges and shaped for special purposes. 



Proechidna. — This is the name given to an animal which 

 in New Guinea takes the place of the Echidna of Australia. 

 The prefix pro is probably intended to denote substitution. 

 It is objectionable, since it is not in any way descriptive. 

 The two animals are of different species, if not of different 

 genera, having doubtless attained their distinctions as the 

 result of long separation. The Proechidna has only three 



