C 5H ] 
us a Meafure of it, that we may underftand what is 
meant by a double or a triple Force. The Ratio of 
One Force to another cannot be perceived but by a 
Meafure; and that Meafure mud be fettled not by 
mathematical Reafoning, but by a Definition. Let 
any one confider Force without relarion to any other 
Quantity, and fee whether he can conceive one 
Force exactly double to another ; I am fure I cannot, 
nor fhall, till I fhall be endowed with fome new Fa- 
culty ; for 1 know nothing of Force but by its EfFe&s, 
and therefore can meafure it only by its Effe&s. Till 
Force then is defined, and by that Definition a 
Meafure of it afligned, we fight in the dark about a 
vague Idea, which is not fufficiently determined to 
be admitted into any mathematical Propofition. 
And when fuch a Definition is given, the Contro- 
verfy will prefently be ended. 
Sect. 6 . 
Of the Newtonian Meafure of Force . 
You fay, the Force of a Body in Motion is as its 
Velocity : Either you mean to lay this down as a 
Definition as Newton himfclf has done 5 or you mean 
to affirm it as a Propofition capable of Proof. If you 
mean to lay it down as a Definition, it is no more 
than if you fhould fay, I call that a double Force 
which gives a double Velocity to the fame Body, a 
triple Force which gives a triple Velocity, and fo 
on in Proportion. This I intirely agree to; no 
mathematical Definition of Force can be given that 
is more clear and fimple, none that is more agree- 
able to the common Ufc of the Word in Language. 
For, 
