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that Law quam pr oxime, by drawing a Parabolick Line through 
any Number of given Points. And by thefc Improvements 
Mr. Newton had in thofe Days made his Method of Fluxions 
much more univerfal than the Differential Method of 
Mr. Leibnitz, is at prelent. 
This Letter of Mr. Newtons , dated Ottob.r 4. 1676, came 
to theHands of Mr. Leibnitz, in the End of the Winter or Be- 
ginning of the Spring following ; and Mr. Leibnitz, loon after, 
viz. in a Letter dated June n. 1677, wrote back : ClariJJim’t 
Slufii methodum Tangent ium nondum effe abfolutam Celeberrimo 
Newtono affentior. Et jam a multo tempore rem Tangent ium 
gener alius traffavi, f cilicet per dijferentias Ordinatarum. 
Hinc ncminandojn poherum,dy dijferentiam duarum proximarum 
y drc. Here Mr. Leibnitz began firfl; to propofe his Diffe- 
rential Method, and there is not the leall Evidence that he 
knew it before the Receipt of Mr. Newtons lafl: Letter. He 
faith indeed, Jam a multo tempore rem Tangent ium gener alius 
traffavi, ( cilicet per dijferentias Ordinatarum : and fo he affirmed 
in other Letters, that he had invented feveral converging 
Series dired and inverfe before he had the Method of invent- 
ing them ; and had forgot an inverfe Method of Series before 
he knew what ufe to make of ic. But no Man is a Witnels 
in his own Caufe. A Judge would be very unjult, and ad 
contrary to the Law’s of all Nations, who fhould admit any 
Man to be a Witnefs in his own Caule. And therefore it 
lies upon Mr. Leibnitz to prove that he found out this Me- 
thod long before the Receipt of Mr. Newtons Letters. And 
if ife cannot prove this, the Queftion, Who was the firfl In- 
ventor of the Method, is decided. 
The Marquifs De l’ Hofpital ( a Perfon of very great Can* 
dour) in the Preface to his Book De Analyfi quant itatum infinite 
* parvarum, publiihed A.C. 1696. tells us, that a little after 
‘the Publication of the Method of Tangents of DesCartes , 
‘ -Mr. Fermat found alio a Method, which DesCartes himfelf 
* at length allowed to be, for the molt part, more fimple than 
r ' his 
