The prosecution now took up the testimony to establish the _overt_ act and called to the stand Jacob Allbright, Peter Taylor, William Love, Maurice P. Belknap and Edmund B. Dana. These witnesses proved the assemblage of men, some thirty or more, on Blannerhassett’s Island, December 10th, 1806, armed with rifles and pistols, the pretended purpose of which was to descend the Ohio River to the City of New Orleans, and make it the base of operations in an expedition to Mexico; but failed to prove the act of levying war. It was not proved that Burr was present on the Island when the assemblage of the men took place. The only witness, who gave any direct testimony on the overt act sought to be proved was Allbright, and he was discredited on cross-examination. He testified on the night of the flight from the Island that “a man by the name of Tupper (meaning General Tupper), laid his hands upon Blannerhassett, and said: ‘Your body is in my hands, in the name of the Commonwealth.’ Some such words as that he mentioned. When Tupper made that motion, there were seven or eight muskets leveled at him. Tupper looked about him and said ‘Gentlemen, I hope you will not do the like.’ One of the gentlemen who was nearest about two yards off said ‘I’d as leave as not.’ Tupper then changed his speech, and said he wished him to escape safe down the river, and wished him luck.” At the conclusion of the evidence relating directly to the overt act charged in the indictment, counsel for the prosecution attempted to introduce collateral testimony of acts beyond the limits of the jurisdiction of the court; but Colonel Burr and his counsel strenuously objected to such testimony as wholly irrelevant and inadmissible, and moved the court to arrest the evidence on the ground that the United States had failed to prove an overt act, constituting treason, under the Constitution of the United States. The argument on this motion, which was so vital to the further prosecution of the case commenced on the 20th of August, and continued until the 29th of that month, and was “doubtless,” says Parton, “the finest display of legal knowledge and ability of which the history of the American bar can boast.”