[ 43 * ] 
But we are told, that all the Force, which refided 
in the Spring, while bent, is now, upon the Unbend- 
ing of the Spring, communicated to the Body moved. 
I ask therefore, What was that Force, or what kind 
of Force was that, which refided in the Spring, while 
bent, and without Motion ? Was it a bare Prcffure, 
or a moving Force ? A Vis mortua , or a Vis viva ? 
You mull acknowledge, it was a Vis mortua , a bare 
Preffure, and nothing more. But the Force commu- 
nicated to the Body, and which now refides in the 
Body in Motion, is a Vis viva , a moving Force. 
This therefore is not the fame Force, nor a Force of 
the fame kind, as that which refided in the bent 
Spring. 
It will be faid, however, That the Force of the 
bent Spring is intirely exhaufted in giving the Body its 
moving Force. I ask therefore again, What is it I am to 
underhand by thefe Words, The Force of the Spring is 
intirely exhaufted ? If the Meaning be, that the Spring 
could not polTibly give that fame Body any greater 
moving Force, than what it has already given, I 
allow it : But this does not prove, that the fame 
Spring, bent afrefh to the fame Degree, or an equal 
Spring equally bent, cannot give a greater Force to 
a greater Body. 
But if the Meaning of thefe Words be, That the 
Spring cannot give a greater moving Force to any 
Body whatfoever, I muft anfwer, That this is taking 
for granted the very Point which is in Difpute. For the 
oppofite Party pretend, That a Body of four Times 
the Bulk, will receive twice the moving Force in 
twice the Time, from the Preffure of the fame Spring 
I i i 2 in 
