In the spring of 1796 he spent three months at Philadelphia and delivered there a set of discourses on the Evidences of Revelation, which he composed with a view to counteract the effect produced by the writings of unbelievers, which, as might be expected, was very great in a country where rational opinions in religion were but little known, and where the evidences of revelation had been but little attended to. It was a source of great satisfaction to him, and what he had little previous reason to expect, that his lectures were attended by very crowded audiences, including most of the members of the congress of the United States at that time assembled at Philadelphia, and of the executive officers of the government. These discourses which, in a regular and connected series, placed Christianity, and the evidences of its truth, in a more clear and satisfactory point of view than it had been usually considered in this country, attracted much attention, and created an interest in the subject which there is reason to believe has produced lasting effects. My father received assurances from many of the most respectable persons in the country, that they viewed the subject in a totally different light from what they had before done, and that could they attend places of worship, where such rational doctrines were inculcated, they should do it with satisfaction. As my father had through life considered the office of a Christian minister as the most useful and honourable of any, and had always derived the greatest satisfaction from fulfilling its duties, particularly from catechizing young persons, the greatest source of uneasiness therefore to him at Northumberland was, that there was no sufficient opportunity of being useful in that way. Though he was uniformly treated with kindness and respect by the people of the place, yet their sentiments in religion were so different from his own, and the nature and tendency of his opinions were so little understood, that the establishment of a place of Unitarian worship perfectly free from any calvinistic or Arian tenet, was next to impossible. All therefore that he could do in that way was, for the two or three first years, to read a service either at his own or at my house, at which a few (perhaps a dozen) English persons were usually present, and in time, as their numbers increased he made use of a school room near his house, where from twenty to thirty regularly attended, and among them some of the inhabitants of the place, who by degrees began to divest themselves of their prejudices with respect to his opinions. However small the number of persons attending, he administered the Lord’s supper, a rite upon which he always laid particular stress.