A HISTORY OF SCIENCE 



"These figures," says Mortillet, "are certainly not exag- 

 gerated. It is even probable that they are below the truth. 

 Constantly new discoveries are being made that tend to re- 

 move farther back the date of man's appearance." We see, 

 then, according to this estimate, that about a quarter of a 

 million years have elapsed since man evolved to a state that 

 could properly be called human. This guess is as good as 

 another, and it may advantageously be kept in mind, as it 

 will enable us all along to understand better than we might 

 otherwise be able to do the tremendous force of certain prej- 

 udices and preconceptions which recent man inherited from 

 his prehistoric ancestor. Ideas which had passed current as 

 unquestioned truths for one hundred thousand years or so 

 are not easily cast aside. 



In going back, in imagination, to the beginning of the pre- 

 historic period, we must of course reflect, in accordance with 

 modern ideas on the subject, that there was no year, no 

 millennium even, when it could be said expressly: " This being 

 was hitherto a primate, he is now a man." The transition 

 period must have been enormously long, and the changes 

 from generation to generation, even from century to century, 

 must have been very slight. In speaking of the extent of 

 the age of man this must be borne in mind : it must be recalled 

 that, even if the period were not vague for other reasons, the 

 vagueness of its beginning must make it indeterminate. 



Bibliographical Notes. A great mass of literature has been 

 produced in recent years dealing with various phases of the 

 history of prehistoric man. No single work known to the 

 writer deals comprehensively with the scientific attainments 

 of early man; indeed, the subject is usually ignored, except 

 where practical phases of the mechanical arts are in question. 

 But of course any attempt to consider the condition of primi- 

 tive man takes into account, by inference at least, his knowl- 

 edge and attainments. Therefore, most works on anthro- 

 pology, ethnology, and primitive culture may be expected to 

 throw some light on our present subject. Works dealing with 

 the social and mental conditions of existing savages are also 

 of importance, since it is now an accepted belief that the an- 

 cestors of civilized races evolved along similar lines and passed 

 through corresponding stages of nascent culture. Herbert 



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