$88 ESSAYS ann OBSERVATIONS 
muft remain unchanged: and we here ab- 
{trac entirely from elafticity, whofe effects 
proceed from a real activity, and have no re- 
lation to what is called the vzs inertiae. To 
find the length of the {pace defcribed by the 
impinging body, we divide the fpace by the 
quantity of matter, which is as it were the 
bafe. And to have the length of the fecond 
{pace defcribed by the two bodies conjointly, 
we muft divide the fame fpace by the 
mafs of matter in both. As the divifor in- 
creafes, the quotient muft diminith in the fame 
proportion. 
WERE we indeed to examine very minute- 
ly the gradual communication of motion 
from one body to another, we fhall find a 
real activity concerned in the operation ; but 
then it is not of that fort againft which we 
are now contending. It is that active force 
known by the name of the attraétion of cobe- 
jfion, which there takes place. When any 
part of a body is pulled or ftruck upon by 
any moving power, it would neceffarily be 
feparated from the other parts, were there 
no cohefion. But, where there is a cohefion, — 
that attractive force muft oppofe the moving 
power. And if either the cohefion be ftrong, 
or 
