Priestley proposed many political reforms, but he was decidedly of opinion that these ought to be brought about gradually. He was in favour of abolishing all religious State establishments, and was a declared enemy to the Church of England. His controversies with the clergy of Birmingham helped to stir up a section of public opinion against him, and to bring about the condemnation of his writings in many parts of the country; he was also unfortunate in making an enemy of Mr. Burke, who spoke against him and his writings in the House of Commons. In the year 1791, the day of the anniversary of the taking of the Bastille was celebrated by some of Priestley's friends in Birmingham. On that day a senseless mob, raising the cry of "Church and King," caused a riot in the town. Finding that they were not checked by those in authority, they after a time attacked and burned Dr. Priestley's meeting-house, and then destroyed his dwelling-house, and the houses of several other Dissenters in the town. One of his sons barely escaped with his life. He himself found it necessary to leave Birmingham for London, as he considered his life to be in danger. Many of his manuscripts, his library, and much of his apparatus were destroyed, and his house was burned. A congregation at Hackney had the courage at this time to invite Priestley to become their minister. Here he remained for about three years, ministering to the congregation, and pursuing his chemical and other experiments with the help of apparatus and books which had been supplied by his friends, and by the expenditure of part of the sum, too small to cover his losses, given him by Government in consideration of the damage done to his property in the riots at Birmingham. But finding himself more and more isolated and lonely, especially after the departure of his three sons to America, which occurred during these years, he at last resolved to follow them, and spend the remainder of his days in the New World. Although Priestley had been very badly treated by a considerable section of the English people, yet he left his native country "without any resentment or ill will." "When the time for reflection," he says, "shall come, my countrymen will, I am confident, do me more justice." He left England in 1795, and settled at Northumberland, in Pennsylvania, about a hundred and thirty miles north-west of Philadelphia. By the help of his friends in England he was enabled to build a house and establish a laboratory and a library; an income was also secured sufficient to maintain him in moderate comfort.