IDENTICAL CHANGES 



of light and darkness a distinct act of creation, 

 and certainly the void matter that transmits light, 

 heat, gravity and magnetism is not affected by 

 these forces as are either the source or the recip- 

 ients of them. 



The primary spheres of void matter cannot be 

 made hotter or colder; they have neither weight 

 nor capacity for momentum, because they are in- 

 capable of change, and every manifestation of 

 force implies a change in the material that shows 

 the action of force. 



Then, in order to manifest force a thing must 

 have organization of particles, and through that 

 organization only can the thing be subject to 

 change, when the particles are in the last instance 

 ultimate, primary and unchangeable. 



That this necessary change in organization can 

 be effected through a loose about vibration, with- 

 out an interchange of ultimate particles, is in the 

 first place improbable, and upon closer investiga- 

 tion it is impossible. (Prop. XVI, B. 1.) 



The circulation of the blood has been recognized 

 for only a comparatively short period, and it seems 

 now strange that any child should not know the 

 fact instinctively; yet we hold that the inside of 

 our green fir tree has been the same for hundreds 

 of years. And the granite of our mountains we 

 deem to be unchanged for ages. Yet all the while 

 tree and mountain and human body have partici- 

 pated in the planetary life of the earth, and the 

 smallest atom of them has been subject to gravity, 

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