Of this world-wide correspondence a portion related to the sore subject of his litigated claim to originality in the discovery of the Differential Calculus,--a matter in which Leibnitz felt himself grievously wronged, and complained with justice of the treatment he received at the hands of his contemporaries. The controversy between him and Newton, respecting this hateful topic, would never have originated with either of these illustrious men, had it depended on them alone to vindicate their respective claims. Officious and ill-advised friends of the English philosopher, partly from misguided zeal and partly from levelled malice, preferred on his behalf a charge of plagiarism against the German, which Newton was not likely to have urged for himself. "The new Calculus, which Europe lauds, is nothing less," they suggested, "than your fluxionary method, which Mr. Leibnitz has pirated, anticipating its tardy publication by the genuine author. Why suffer your laurels to be wrested from you by a stranger?" Thereupon arose the notorious _Commercium Epistolicum_, in which Wallis, Fatio de Duillier, Collins, and Keill were perversely active. Melancholy monument of literary and national jealousy! Weary record of a vain strife! Ideas are no man's property. As well pretend to ownership of light, or set up a claim to private estate in the Holy Ghost. The Spirit blows where it lists. Truth inspires whom it finds. He who knows best to conspire with it has it. Both philosophers swerved from their native simplicity and nobleness of soul. Both sinned and were sinned against. Leibnitz did unhandsome things, but he was sorely tried. His heart told him that the right of the quarrel was on his side, and the general stupidity would not see it. The general malice, rejoicing in aspersion of a noble name, would not see it. The Royal Society would not see it,--nor France, until long after Leibnitz's death. Sir David Brewster's account of the matter, according to the German authorities, Gerhardt, Guhrauer, and others, is one-sided, and sins by _suppressio veri_, ignoring important documents, particularly Leibnitz's letter to Oldenburg, August 27, 1676. Gerhardt has published Leibnitz's own history of the Calculus as a counter-statement. [10] But even from Brewster's account, as we remember it, (we have it not by us at this writing.) there is no more reason to doubt that Leibnitz's discovery was independent of Newton's than that Newton's was independent of Leibnitz's. The two discoveries, in fact, are not identical; the end and application are the same, but origin and process differ, and the German method has long superseded the English. The question in debate has been settled by supreme authority. Leibnitz has been tried by his peers. Euler, Lagrange, Laplace, Poisson, and Biot have honorably acquitted him of plagiarism, and reinstated him in his rights as true discoverer of the Differential Calculus.