Brethren: - We are assembled this evening as a Presbyterian Historical Society. It has occurred to me that it would not be inappropriate to discuss the question, What is Presbyterianism? You will not expect from me an oration. My object is neither conviction nor persuasion; but exposition. I propose to occupy the hour devoted to this address in an attempt to unfold the principles of that system of Church polity which we, as Presbyterians, hold to be laid down in the word of God.