( '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, (hews 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 Tangent thus ducendis ab 
his non abludere. Quod addit y ex hoc eodem fundamento Qua- 
drat ur as quoque reddl faciliores me in hac fententia confirmat ; 
vimirum femper figur a ilia funt quadrabiles-qua funt ad aquationem 
diferentialem. 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 
feme Performances. 
In November 1684 Mr. Leibnitz* publilhed the Elements of 
this Differential Method in the Alda Eruditorum, and illuflra- 
ted it with Examples of drawing Tangents and determining 
Maxima and Minima, and then added. Et hac quidem initia 
funt Geometric cujufdam multofublimioris, ad difficillima d>ptd* 
cherrima qitaque etiam mift<e Mathefeos Problemata pertingentis , 
qua fine calculo differ entiali AUT SIMILI non temere quifi- 
quam pari facilitate trail obit. The W ords 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 queedam ip fins 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 fmgle Letters 
with more brevity. 
* K k The 
