VOL. XXIX.] PHILOSOPHICAL TRANSACTIONS. 135 



preface to the first volume of his works, published in 1695. And in a letter to 

 Mr. Leibnitz, dated Dec. I, 1696, (printed in the 3d vol. of Wallis's works) 

 he gave this account of it: '^ After the last sheet of the preface had been com- 

 posed at the press, a friend of mine, skilled in such matters, and who happened 

 to be abroad at that time, acquainted me that such a method was then spoken 

 of in Holland, and also that it nearly coincided with Newton's method of 

 fluxions ; which made me insert an intimation of it." And in a letter dated 

 April 10, 1695, and lately communicated to the Royal Society, he wrote thus 

 about it : "I wish you would print the two large letters of June and August 

 [he means June and October] 1676. I had intimation from Holland, as de- 

 sired there by your friends, that somewhat of that kind were done; because 

 your notions (of fluxions) pass there with great applause by the name of 

 Leibnitz's calculus differentials. You are not so kind to your reputation (and 

 that of the nation) as you might be, when you let things of worth lie by you 

 so long, till others carry away the reputation that is due to you. I have endea- 

 voured to do you justice in that point, and am now sorry that I did not print 

 those two letters verbatim." 



The short intimation of this matter, which Dr. Wallis inserted into the said 

 preface, was to this effect : " In the 2d volume, among other things, there is 

 Mr. Newton's method of fluxions, as he calls it, of a like nature with Mr. 

 Leibnitz's differential calculus, as he terms it, (as any one who compares both 

 methods will easily find ; only under different forms of expression) which I have 

 described cap. 9 1 , and especially cap. 95, from Mr. Newton's two letters, or 

 one of them, dated June 13 and October 24, 1676, written to Mr. Olden- 

 burg, and to be communicated to Mr. Leibnitz (almost in the same words, or 

 at least with little variation, from what is contained in the said letters) where he 

 explains this method to Mr. Leibnitz, which he had invented about 10 years 

 before, if not more, that is in 1666 or 1065 ; which I hint, that none may 

 allege, I have said nothing of this calculus differential is." 



On this, the editors of the Acta Lipsiensia, for June, the following year, in 

 the stile of Mr. Leibnitz, in giving an account of these first two volumes of 

 Dr. Wallis, took notice of this clause in the Doctor's preface, and complained, 

 not of his saying that Mr. Newton, in his two letters above-mentioned, ex« 

 plained to Mr. Leibnitz the method of fluxions found by him above 10 years 

 before; but that while the Doctor mentioned the differential calculus, and said 

 that he did it, " that none might allege that he had said nothing of the differ- 

 ential calculus," he did not tell the reader that Mr. Leibnitz had this calculus 

 at that time when those letters passed between him and Mr. Newton, by means 



