The excellency and advantage of doing good : represented in a sermon preached before the honourable Trustees for Establishing the Colony of Georgia in America, and the Associates of the late reverend Dr. Bray, on their anniversary meeting, March 17, 1747-8 : in the parish church of St. Margaret, Westminster : to which is annex'd a letter of Samuel Loyd, Esq., concerning the nature and goodness of the Georgia silk.