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26 ESSAYS ann OBSERVATIONS 
Or THE COMMUNICATION 
or M O.T LO UN, 
H E Communication of motion from 
one body to another, has been ex- 
tremely puzling to metaphyficians; tho’ not 
to practical philofophers, who make no dif- 
ficulty to fuppofe, that motion a€ually pafles 
out of one piece of matter into another. Let 
us figure one billiard ball at reft, and ano- 
ther directed upon it with a certain velocity. 
It is underftood that part of the motion of 
the impingeing ball paffes into that which is 
at reft, after which it proceeds to move with 
‘that degree of velocity which is communi- 
cated to it. This account of the matter ap- 
pears to me altogether abfurd. Motion can- 
not fubfift by itfelf to be transferred from 
place to place, or from body to body. It is 
one of the qualities or properties of matter ; 
and it is no lefs repugnant to the very conce- 
ption of the thing, that the motion of one 
body 
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