A discourse concerning the conversion of the heathen Americans, and the final propagation of Christianity and the sciences to the ends of the earth : In two parts. Part I. Preached before a voluntary convention of the Episcopal clergy of Pennsylvania, and places adjacent, at Philadelphia, May 2d, 1760; and published at their joint request. Part II. Preached before the trustees, masters and scholars of the College and Academy of Philadelphia, at the first anniversary commencement. /