Much of Hamilton’s clouded reputation in New York stemmed from the murder trial of Charles Stielow who, in 1915, was accused of shooting Charles Phelps and his housekeeper in West Shelby. Hamilton had appeared for the prosecution. After tests and a minute examination of Stielow’s revolver and of the three bullets taken from Phelps’ body and the one from that of his housekeeper, he testified that only Stielow’s revolver could have fired the bullets. Principally because of this testimony Stielow was found guilty and sentenced to death. Later he was proved to be innocent and pardoned. In a post-trial review of the evidence Max Poser, an expert in applied optics with the Bausch & Lomb Optical Company, demonstrated that the bullets taken from the bodies had not come from the Stielow revolver. “The opinion expressed by the expert Hamilton in his evidence at the trial,” Poser concluded, “was worthless.” The setback, however, did not seem to hamper Hamilton’s career. It did not take Hamilton long, after inspecting the Sacco-Vanzetti exhibits, to come to his conclusions. In the motion, filed on April 30, 1923, he claimed that by using a Bausch & Lomb compound microscope he was able to ascertain discrepancies between the markings on the test bullets from Sacco’s pistol and the markings on Bullet III. According to his measurements the land and groove widths in the barrel of Sacco’s Colt agreed with the land and groove widths on the test bullets but not with the mortal bullet. He also found that a microscopic examination of the Fraher shells eliminated the possibility of any one of them having been fired in the Colt. Because of a difference in the cannelures, he contended that Bullet III was not manufactured at the same time as the six Winchester cartridges found on Sacco. Augustus Gill, Professor of Technical Chemical Analysis at the Massachusetts Institute of Technology, had been engaged to assist Hamilton. His tabulations, made under different conditions, varied somewhat from Hamilton’s. Nevertheless, he was convinced from his own measurements “that the so-called mortal bullet never passed through the Sacco gun.” As for Vanzetti’s revolver, Hamilton maintained that it had not been fitted with a new hammer, because an essential screw did not show marks of having been removed.