In his account on Leibniz in A Short Account of the History of Mathematics, W.W. Rouse Ball wrote the following: ".... but when, in 1849, C. J. Gerhardt examined Leibniz' papers he found among them a manuscript copy, the existence of which dad been previously unsuspected, in Leibniz handwriting, of extracts from Newton's De Analysi .......... together with notes on their expression in the differential notation." In another paragraph he writes: ".... on more than one occasion he deliberately altered or added to important letters ...... before publishing them, and what is worse, that a material date in one of his manuscripts has been falsified. (1675 being altered to 1673) ....."
These extracts are found on pages 357 and 360 respectively in the Dover reprint of 1960.
I do not think that these facts prove or disprove anything in the Newton-Leibniz dispute. Yet I was rather surprised that R.S. Westfall does not mention these points at all in his admirable work Never at Rest. My question to the historia list members is: Why did Westfall fail to mention these points?