KNOWLEDGE OF EXTENSION. 101 



cess of inferring. Our knowledge of extension or 

 magnitude, too, is an inference ; and it is impossi- 

 ble for any one to say how many millions of feel- 

 ings a child must sum up before it can feel the 

 length of its own finger, or make sure of touching 

 the finger of the left hand with the finger of the 

 right. It is clear, however, that in this dawn and 

 birth of knowledge this fountain and day-spring 

 of all ingenuity and of all action, we borrow no- 

 thing from the eye; for we can lay our finger 

 upon any reachable point of our own body with 

 our eyes shut, as accurately as we can with the 

 eyes open, if, indeed, not more accurately. 



Any one may be convinced of the truth of this, 

 by extending his arms, clenching his hands, except 

 the fore fingers, and then bringing these to touch 

 each other, in front where he sees them, and be- 

 hind him, or over his head, where he sees them 

 not ; and, if he will but shut his eyes at the same 

 time so as to prevent the distraction of sight from 

 without, he will find that the unseen touch is 

 more easily and more accurately performed, than 

 that upon which the eye looks, and, as we sup- 

 pose, directs with the most studied attention. 



Thus the gravitation of matter is not only the 

 most general property of matter, but it is the 

 source and foundation of all that we can observe 

 or know about material things ; for our first sensa- 

 tions, which the mind must have before it can 

 either compare or infer, are, and can be, nothing 

 but resistances of gravitation to the action of our 

 muscles ; and the probability, nay, the certainty, 

 is, that we feel them in the weight of the muscles 

 themselves, before we can have the slightest notion 



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