As in his own student days, the Hall met for only two months in each year, and the professors therefore did not need to give up their ministerial charges.  So he remained in Berwick, where his congregation were very proud of the new honour that had come to their minister, and that was in some degree reflected on them.  Instead of “the Doctor” they now spoke of him habitually as “the Professor,” and presented him with a finely befrogged but somewhat irrelevant professor’s gown for use in the pulpit at Wallace Green.

Dr. Cairns prepared two courses of lectures for his students—­one on the History of Apologetics, and the other on Apologetics proper, or Christian Evidences.  For the former, his desire to go to the sources and to take nothing at second-hand led him to make a renewed and laborious study of the Fathers, who were already, to a far greater extent than with most theologians, his familiar friends.  His knowledge of later controversies, such as that with the Deists, which afterwards bore fruit in his work on “Unbelief in the Eighteenth Century,” was also widened and deepened at this time.  These historical lectures were almost overweighted by the learning which he thus accumulated; but they were at once massive in their structure and orderly and lucid in their arrangement.

In the other course, on Christian Evidences, he did not include any discussion on Theism which—­probably because of his special familiarity with the Deistical and kindred controversies, and also because the modern assaults on supernatural Christianity from the Evolutionary and Agnostic standpoint had not yet become pressing—­he postulated.  And, discarding the traditional division of the Evidences into Internal and External, he classified them according to their relation to the different Attributes of God, as manifesting His Power, Knowledge, Wisdom, Holiness, and Benignity.  With this course he incorporated large parts of his unfinished treatise on “The Difficulties of Christianity,” which, after he had thus broken it up, passed finally out of sight.

The impression which he produced on his students by these lectures, and still more by his personality, was very great.  “I suppose,” writes one of them, “no men are so hypercritical as students after they have been four or five years at the University.  To those who are aware of this, it will give the most accurate impression of our feeling towards Dr. Cairns when I say that, with regard to him, criticism could not be said to exist.  We all had for him an appreciation which was far deeper than ordinary admiration; it was admiration blended with loyalty and veneration."[16] Specially impressive were the humility which went along with his gifts and learning, and the wide charity which made him see good in everything.  One student’s appreciation of this latter quality found whimsical expression in a cartoon which was delightedly passed from hand to hand in the class, and which represented Dr. Cairns cordially shaking hands with the Devil.  A “balloon” issuing from his mouth enclosed some such legend as this:  “I hope you are very well, sir.  I am delighted to make your acquaintance, and to find that you are not nearly so black as you are painted.”