PREHISTORIC SCIENCE 



which came to be known finally as planets, or wander- 

 ing stars. The wandering propensities of such brilliant 

 bodies as Jupiter and Venus cannot well have escaped 

 detection. We may safely assume, however, that these 

 anomalous motions of the moon and planets found no 

 explanation that could be called scientific until a rela- 

 tively late period. 



3. Turning from the heavens to the earth, and ig- 

 noring such primitive observations as that of the dis- 

 tinction between land and water, we may note that 

 there was one great scientific law which must have 

 forced itself upon the attention of primitive man. 

 This is the law of universal terrestrial gravitation. The 

 word gravitation suggests the name of Newton, and it 

 may excite surprise to hear a knowledge of gravitation 

 ascribed to men who preceded that philosopher by, say, 

 twenty -five or fifty thousand years. Yet the slightest 

 consideration of the facts will make it clear that the 

 great central law that all heavy bodies fall directly 

 towards the earth, cannot have escaped the attention 

 of the most primitive intelligence. The arboreal 

 habits of our primitive ancestors gave opportunities 

 for constant observation of the practicalities of this 

 law. And, so soon as man had developed the mental 

 capacity to formulate ideas, one of the earliest ideas 

 must have been the conception, however vaguely 

 phrased in words, that all unsupported bodies fall tow- 

 ards the earth. The same phenomenon being observed 

 to operate on water-surfaces, and no alteration being 

 observed in its operation in different portions of man's 

 habitat, the most primitive wanderer must have come 

 to have full faith in the universal action of the ob- 



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