Rather more than a year and a half after his ordination, in May 1847, the Secession Church in which he had been brought up, and of which he was now a minister, entered into a union with another of the Scottish non-Established Churches, the Synod of Relief.  There was thus formed the United Presbyterian Church, with which his name was afterwards to be so closely associated.  The United Church comprised five hundred and eighteen congregations, of which about fifty were, like those in Berwick, in England; the nucleus of that English Synod which, thirty years later, combined with the English Presbyterian Church to form the present Presbyterian Church of England.  References in his correspondence show that this union of 1847, which afterwards had such happy results, excited at the time little enthusiasm, and was entered into largely as a matter of duty.  “It is,” he writes, “like the union, not of two globules of quicksilver which run together of themselves, but of two snowballs or cakes of mud that need in some way very tough outward pressure.  I hope that the friction will elicit heat, since this neither cold nor hot spirit is not to edification.”

The other letters of this period range over a wide variety of subjects.  With John Clark he compares experiences of ministerial work; with John Nelson he discusses European politics as these have been affected by the events of the “year of revolutions,” 1848; with George Wilson he discourses on every conceivable topic, from abstruse problems of philosophy and theology to the opening of the North British Railway; while his mother and his brothers, William and David, the latter of whom about this time left his work in the Dunglass woods to study for the ministry, are kept in touch with all that he knows they will best like to hear about.  But in all this wide field of human life and thought and activity, which he so eagerly traverses, it is quite evident that what attracts him most is the relation of it all to a higher and an eternal order.  With him the main interest is a religious one.  Without an atom of affectation, and without anything that is at all morbid on his part, he reveals this at a hundred points.  In this connection a letter which he wrote to Sir William Hamilton and which has since become well known, may be quoted here; and it, with Sir William’s reply, will fittingly conclude the present chapter.  This letter bears date November 16, 1848, and is as follows:—­

“I herewith enclose the statement respecting the Calabar Mission of our Church, which I take blame to myself for having so long delayed to send.  My avocations are very numerous, and a habit of procrastination, where anything is to be written, has sadly grown on me with time.  I cannot even send you this brief note without testifying, what I could not so well utter in your presence, my unabated admiration of your philosophical genius and learning, and my profoundly grateful sense of the important benefits received