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I/VI. Note on the Occurrence of Flint Implements in the Drift. 

 By Balfour Stewart, A.M. 

 To the Editors of the Philosophical Magazine and Journal. 

 Gentlemen, 



WITHOUT pretending to be a geologist, I may yet be per- 

 mitted to point out a general property of matter which 

 may perhaps tend to modify the conclusions which some have 

 derived from the occurrence of flint implements in the drift. 

 Taking it for granted that such implements have been found in 

 this deposit, and that they are the work of human hands, I do 

 not yet feel prepared to allow the great antiquity of our race as 

 a logical conclusion. 



May it not be laid down as an axiom in physical science, that 

 no substance whatever possesses a quality in such perfection as 

 to exclude absolutely the opposite and antithetical quality ? 



In proof of this statement, it may be asserted that the most 

 mobile liquids with which we are acquainted are yet viscous in 

 some degree, and have therefore so far the properties of a solid ; 

 while, on the other hand, some of apparently the most solid 

 bodies exhibit to some extent the properties of a liquid. 



A very notable instance of this latter class is found in glacier 

 ice, which, as Principal Forbes has shown, behaves like a some- 

 what viscous body, gradually moving down its bed, although it 

 may be nearly two centuries before a particle finds its way from 

 the top to the bottom of this river of ice. 



May not the drift and superficial deposits which cover the 

 surface of our globe be of this character — somewhat resembling 

 mud, only very much more consistent, but yet not absolutely 

 free from all traces of fluidity ? 



If this be allowed, it follows that bodies of some size placed in 

 this deposit will in the course of ages find their way from the top 

 to the bottom, if they possess a higher specific gravity than the 

 drift in which they are placed. I think I am right in asserting 

 that flint implements are of this nature ; and it therefore becomes 

 a question whether these may not have a slow downward secular 

 motion in this deposit. 



The consequence of such would be that, if merely judged by 

 their position in the drift, w r e should ascribe to these implements 

 a much greater age than they are really entitled to. This pecu- 

 liar motion would, however, not take place in the case of human 

 remains coeval with the flints, these remains being of small spe- 

 cific gravity ; and we may thus perhaps explain the very remark- 

 able fact, that while flint implements in abundance have been 

 found in the drift, no human remains have as yet been discovered. 

 I need hardly remark that the downward secular motion of the 

 flints which is here supposed must be an exceedingly slow one, 



