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fequence of all the Differences. And if he did not under- 
ftand it when he added that Scholium to the End of the Book, 
which was in the \ ear 1704* it muff have been becaufe he 
had then forgot it. And fo the Queflion is only whether 
he had forgot the Method of fecond and third Differences 
before the Year 1704. 
In the Tenth Propofition of the fecond Book of his V rivet* 
fu ThilofophU, in deferibing fome of the Ufes of the Terms 
of a converging Series for folving of Problemes, he tells us 
that if the firfl Term of the Series re- 
prefents the Ordinate BC of any Curve 
Line ACG,* and CBDI be a Paralle- 
logram infinitely narrow, whofe Side 
D/ cuts the Curve in G and its Tan- 
gent C F in F, the fecond Term of the 
Series will reprefent the Line I F, and 
the third Term the Line FG. Now the 
Line FG is but half the fecond Difference of the Ordinate : 
and therefore Mr. Newton when he wrote his Principia, put 
the third Term of the Series equal to half of the fecond Diffe- 
rence of the firft Term, and by confequence had not then for- 
gotten the Method of fecond Differences. 
In writing that Book, he had frequent occafion to confider 
the Increafe or Decreafe of the Velocities with which Quanti- 
ties are generated, and argues right about it- That Increafe 
or Decreafe is the fecond Fluxion of the Quantity, and there- 
fore he had not then forgotten the Method of fecond Flu- 
xions. 
In the Year 1692, Mr. Nervton, attheRequefl of Dr .Wallis, 
lent to him a Copy of the firfl Propbfition of the Book of 
Quadratures, with Examples thereof in firfl, fecond and third 
Fluxions .* as you may fee in the fecond Volume of the Do*- 
dor’s Works, 391, 391,393 and396. And therefore he 
had not then forgotten the Method of fecond Fluxions. 
Liz ^ Nor 
