The Meafure of this Force is the Weight with 
which the Table is prefied, or the Rope is ftretched, 
or the Spring is bent. 
And that Meafure being acknowledged by all 
Writers, there is no Difpute about this Sort of Force, 
notwithflanding the Diverfity of Appellations by 
which it is called. 
The Force of a Body in Motion is on all hands 
agreed to be a Power refiding in that Body, fo long 
as it continues its Motion ; by means of which it is 
able to remove Obftacles lying in its Way; to lef- 
fen, deftroy, or overcome, the Force of any other 
moving Body, which meets it in an oppoftte Di- 
rection ; or to furmount any dead Prefiure or Refin- 
ance, as Tenfion, Gravity, FriCtion, &c. for fome 
time ; but which will be leiien’d or deftroy’d by fuch 
Obftacles, or by fuch Refiftance, as lefiens or de- 
ftroys the Motion of the Body. 
This is called moving Force, Vis motrix, and by 
fome late Writers, Vis viva, to diftinguifh it from 
the Vis mortua fpoken of before : And by thefe Ap- 
pellations, however different, the fame Thing is un« 
derftood by all Mathematicians j namely, That Power 
of difplacing Obftacles, withftanding oppoftte moving 
Forces, or overcoming any dead Refiftance, which 
refides ia a moving Body, and which, in Whole 
or in Part, continues to accompany it, fo long- as 
the Body moves. 
But about the Meafure of this Sort of Force, Ma- 
thematicians are divided into two Parties: And, in 
order to ftate the Cafe fairly between them, it will 
be neceftary to fhew how far the two Parties agree, 
and in what Point their Difagreement confifts. 
Both 
