188 FRAGMENTS OF SCIENCE. 



infant. Thus it happens that the European inherits 

 from twenty to thirty cubic inches more of brain than 

 the Papuan. Thus it happens that faculties, as of 

 music, which scarcely exist in some inferior races, 

 become congenital in superior ones. Thus it happens 

 that out of savages unable to count up to the number 

 of their fingers, and speaking a language containing 

 only nouns and verbs, arise at length our Newtons and 

 Shakspeares.' 



8. 



At the outset of this Address it was stated that 

 physical theories which lie beyond experience are 

 derived by a process of abstraction from experience. 

 It is instructive to note from this point of view the 

 successive introduction of new conceptions. The idea 

 of the attraction of gravitation was preceded by the 

 observation of the attraction of iron by a magnet, and 

 of light bodies by rubbed amber. The polarity of mag- 

 netism and electricity also appealed to the senses. It 

 thus became the substratum of the conception that 

 atoms and molecules are endowed with attractive and 

 repellent poles, by the play of which definite forms of 

 crystalline architecture are produced. Thus molecular 

 force becomes structural. 1 It required no great bold- 

 ness of thought to extend its play into organic nature, 

 and to recognise in molecular force the agency by 

 which both plants and animals are built up. Jp this 

 way, out of experience arise conceptions which are 

 wholly ultra-experiential. None of the atomists of 

 antiquity had any notion of this play of molecular 

 polar force, but they had experience of gravity, as 

 manifested by falling bodies. Abstracting from this, 



1 See Art. on Matter and Force, or 'Lectures on Light,' No. IIL 



