f *8 6 . ) 
of their Mi fabrication of the Experiments they build 
upon. 
The Effect of a Force itnprefs’d on a moveable 
Body, is the Motion of that Body from cne Place to 
another. Now forafmuch as the Effeffi cannot but be 
proportional to its Caufe , hence Mr. Leibnitz (whom 
the other Gentlemen have follow’d) contends that the 
Space deferih'd by a Body in falling, is proportional to 
the Force by which it is impell’d during its Fall , 
and that the Force acquir’d by a Body in falling, is 
proportional to the Space it has deferibed in its Fall. 
Which Space being agreed to be as the Square of the 
Velocity (as being proportional to the Velocity and to 
the Time taken together ) hence they infer that the 
Force likewife is as th t Square of the Velocity. 
But from what has been faid, ttis plain, that the 
Space deferibed in thefe and all other the like Cafes, 
is not as the Force only, but as the Force and as the 
Time wherein the Force ads ; that is to fay, as the 
Square of the Force. For the Caufe of the Quantity 
of the Space deferibed , is not barely the Quantity of 
the Force , but alfo the Continuance of the Time 
wherein the Force ads. The Force therefore and the 
Time taken together , being necettarily as the Space 
deferibed } as the Velocity and the Time taken toge- 
ther, are on all Hands acknowledg’d to be ^ it follows 
that the Velocity and the Force are equal, and not the 
Force as the Square of the V zlocity. 
When two unequal Bodies fattened at the Ends of 
the Arms of a Balance of unequal Length , counter- 
poife each other, and vibrate in equal Times ^ as they 
mutt necelfarily do, being fafened to the Arms of the 
fame Balance : which is an Obfervation Mr. Leibnitz 
lays great Strefs upon : In That Cafe indeed the Forces 
? will 
