Dr. Keill, as the representative of Newton’s friends, could not brook this base attack upon his countryman. In a letter printed in the Philosophical Transactions for 1708, he maintained that Newton was “beyond all doubt” the first inventor of fluxions. He referred for a direct proof of this to his letters published by Wallis; and he asserted “that the same calculus was afterward published by Leibnitz, the name and the mode of notation being changed.” If the reader is disposed to consider this passage as retorting the charge of plagiarism upon Leibnitz, he will readily admit that the mode of its expression is neither so coarse nor so insidious as that which is used by the writer in the Leipsic Acts. In a letter to Hans Sloane, dated March, 1711, Leibnitz complained to the Royal Society of the treatment he had received. He expressed his conviction that Keill had erred more from rashness of judgment than from any improper motive, and that he did not regard the accusation as a calumny; and he requested that the society would oblige Mr. Keill to disown publicly the injurious sense which his words might bear. When this letter was read to the society, Keill justified himself to Sir Isaac Newton and the other members by showing them the obnoxious review of the Quadrature of Curves in the Leipsic Acts. They all agreed in attaching the same injurious meaning to the passage which we formerly quoted, and authorized Keill to explain and defend his statement. He accordingly addressed a letter to Sir Hans Sloane, which was read at the society on the 24th May, 1711, and a copy of which was ordered to be sent to Leibnitz. In this letter, which is one of considerable length, he declares that he never meant to state that Leibnitz knew either the name of Newton’s method or the form of notation, and that the real meaning of the passage was, “that Newton was the first inventor of fluxions or of the differential calculus, and that he had given, in two letters to Oldenburg, and which he had transmitted to Leibnitz, indications of it sufficiently intelligible to an acute mind, from which Leibnitz derived, or at least might derive, the principles of his calculus.” The charge of plagiarism which Leibnitz thought was implied in the former letter of his antagonist is here greatly modified, if not altogether denied. Keill expresses only an _opinion_ that the letter _seen_ by Leibnitz contained intelligible indications of the fluxionary calculus. Even if this opinion were correct, it is no proof that Leibnitz either saw these indications or availed himself of them, or if he did perceive them, it might have been in consequence of his having previously been in possession of the differential calculus, or having enjoyed some distant view of it. Leibnitz should, therefore, have allowed the dispute to terminate here; for no ingenuity on his part, and no additional facts, could affect an opinion which any other person as well as Keill was entitled to maintain.