The trades unions were then proscribing the employment of colored mechanics. Many who had worked at skilled labor were by this prejudice forced to do drudgery or find employment in other cities. The president of a "mechanical association" was publicly tried in 1830 by that organization for the crime of assisting a colored youth to learn a trade.[20] A young man of high character, who had at the cabinet-making trade in Kentucky saved enough to purchase his freedom, came to Cincinnati about this time, seeking employment. He finally found a position in a shop conducted by an Englishman. On entering the establishment, however, the workmen threw down their tools, declaring that the Negro had to leave or that they would. The unfortunate "intruder" was accordingly dismissed. He then entered the employ of a slaveholder, who at the close of the Negro's two years of service at common labor discovered that the black was a mechanic. The employer then procured work for him as a rough carpenter. By dint of perseverance and industry this Negro within a few years became a master workman, employing at times six or eight men, but he never received a single job of work from a native-born citizen from a free State.[21] The hardships of the Negroes of this city, however, had just begun. The growth of a prejudiced public opinion led not only to legal proscription and social ostracism but also to open persecution. With the cries of the Southerners for the return of fugitives and the request of white immigrants for the exclusion of Negroes from that section, came the demand to solve the problem by enforcing the "Black Laws." Among certain indulgent officials these enactments had been allowed to fall into desuetude. These very demands, however, brought forward friends as well as enemies of the colored people. Their first clash was testing the constitutionality of the law of 1807. When the question came up before the Supreme Court, this measure was upheld.[22] Encouraged by such support, the foes of the Negroes forced an execution of the law. The courts at first hesitated but finally took the position that the will of the people should be obeyed. The Negroes asked for ninety days to comply with the law and were given sixty. When the allotted time had expired, however, many of them had not given bonds as required. The only thing to do then was to force them to leave the city. The officials again hesitated but a mob quickly formed to relieve them of the work. This was the riot of 1829. Bands of ruffians held sway in the city for three days, as the police were unable or unwilling to restore order. Negroes were insulted on the streets, attacked in their homes, and even killed. About a thousand or twelve hundred of them found it advisable to leave for Canada West where they established the settlement known as Wilberforce.[23]