( >97 ) 
And whereas Mr. Newton had faid that his Method in draw- 
ing of Tangents, and determining Maxima, and Minima, &c, 
proceeded without flicking at Surds : Mr. Leibnitz in the 
next Place, fhews how this Method of Tangents maybe im- 
proved fo as not to flick at Surds or Fra&ions, and then adds: 
Arbitror qua celare voluit Newtonus de T anient ibus ducendis ab 
his non abludere. Quod addit , ex hoc eodem fundamento £>ua- 
draturas quoque reddi faciliores me in hac fententia confirmat ; 
nimirum [emper figur a ilia funt quadrabilesqua funt ad aquationem 
differentialem. By which Words, compared with the preceding 
Calculation, its manifefl that Mr. Leibnitz at this time under- 
flood that Mr. Newton had a Method which would do allthefe 
things, and had been examining whether Dr. Barrow’s Diffe- 
rential Method of Tangents might not be extended to the 
fame Performances. 
In November 1684 Mr. Leibnitz, publifhed the Elements of 
this Differential Method in the AH a Eruditorum , and illuflra- 
ted it with Examples of drawing Tangents and determining 
Maxima and Minima, and then added. Et hac qutdem initio, 
funt Geometric cujufdam multo fnblimioris, ad difficillima & pul- 
chenima q/taque etiam mift<e Mathefeos Problemata pertingentis, 
qua fine calculo differ entiall AUT SIMILI non temere quif- 
quam pari facilitate traffabit. The Words AUT SIMILI 
plainly relate to Mr. Newtons Method. And the whole Sen- 
tence contains nothing more than what Mr. Newton had affir- 
med of his general Method in his Letters of 1672 and 1676. 
And in the AH a Eruditorum of June 1686, pag. 297: 
Mr Leibnitz added : Malo autem dx & fimilia adhibere quam 
lit eras pro illis , quia iflud dx eft modificatio qutedam ipftus x, 
&c. He knew that in this Method he might have ufed 
Letters with Dr. Barrow , but chofe rather to ufe the new 
Symbols dx and dy, though there is nothing which can be 
done by thefe Symbols, but may be done by fingle Letters 
with more brevity. 
* Kk 
The 
