14 THE BEGINNINGS OF LIFE. 



the electricity so evolved may immediately after ex- 

 hibit itself as heat, light, or chemical affinity. Faraday's 

 discovery of the effect of magnetism on polarized light, 

 as well as the discovery that change of magnetic state 

 is accompanied by heat, point to further like con- 

 nections. Lastly, various experiments show that the 

 magnetization of a body alters its internal structure ; 

 and that, conversely, the alteration of its internal struc- 

 ture, as by mechanical strain, alters its magnetic con- 

 dition/ We need allude to all these possibilities of 

 change no further ; those who wish for additional in- 

 formation may find it in Mr. Grove's work. 



The most attentive consideration of the facts forces 

 us to the conclusion even to an irresistible belief 

 that though continually varying in its modes, Force 

 itself is indestructible or persistent. As Mr. Herbert 

 Spencer says, such an allegation really amounts to this, 

 that a priori possibilities and experimental evidence 

 alike warrant us in the belief c that there cannot 

 be an isolated force beginning and ending in no- 

 thing ; but that any force manifested implies an 

 equal antecedent force from which it is derived, and 

 against which it is a reaction. Further, that the force 

 so originating cannot disappear without result- but 

 must expend itself in some other manifestation of 

 force, which, in being produced, becomes its reaction ; 

 and so on continually.' 



If forces are nothing but the inseparable qualities, 

 attributes, or affections of matter, and if matter is 



