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POSTSCRIPT. 
U PON reviewing the Reftedions on the Quadrature of the 
Circle in Page 212* I believe it may be neceffary for me, to 
prevent any Miftake that may arife from the different Opinions that 
obtain about the Nature of Mathematical Quantity, to explain my- 
felf a Jittie upon that head • as alfo to add a few Words to fhew how 
the Method of Quadrature by limiting Polygons, takes place in other 
Figures as well as the Circle. 
I take then a Mathematical Quantity, and that for which any Symbol 
: is put, to be nothing elfe but Number with regard to fome Meafure 
which is confidered as one. For we cannot know precifely and de- 
terminately, that is. mathematically, how much any thing is, but by 
means of Number. The Notion of continued Quantity, without 
regard to any Meaftire, is indiftind and confufed ; and although fome 
Species of fuch Quantity, confidered phyfically, may be defcribed by 
Motion, as Lines by Points, and Surfaces by Lines, and fo on ; yet 
the Magnitudes or Mathematical Quantities are not made by that Mo- 
tion, but by numbering according to a Meafure. 
Accordingly, all the feveral Notations that are found neceffary to 
exprefs the Formations of Quantities, do refer to fome Office or Pro- 
perty of Number or Meafure j but none can be interpreted to fignify 
continued Quantity as fuch. 
Thus fome Notations are found requifite to exprefs Number in its 
ordinal Capacity, or the Nuvierus Numer ans^ as when one follows or 
precedes another, in the firft, fecond or third Place from that upon 
which it depends; as the Quantities x,x, x,tx, x, referring to the 
principal one x. 
So, in many Cafes, a Notation is found neceffary to be given to a 
Meafure as a Meafure ; as for Inftance, Sir Ifaac Ne<wtoris Symbol for 
a Fluxion * ; for this ftands for a Meafure of fome kind, and accord- 
ingly he ufually puts an Unit for it, if it be the principal one upon 
which the reft depend. 
So fome Notations are exprefly to fliew a Number in the form of its 
Compofition, as the Index to the Geometrical Power * n denoting the 
Number of equal Fadors which go to the Compofition of it, or whac 
is analogous to fuch. 
But that there is no Symbol or Notation but what refers to diferete 
Quantity, is manifeft from the Operations, which are all Arithmetical. 
And hence it is, there are fo many Species of Mathematical Quan- 
tity as there are Forms of compofite Numbers, or Ways in the Compo- 
pofttion of them , among which there are two more eminent for their 
Simplicity 
