at once of truth and happiness. "But I check myself in this unwonted strain, which only your long-continued and singular kindness could have emboldened me to attempt; and with the utterance of the most fervent wishes for your health, academical success, and inward light and peace, I remain your obliged friend and grateful pupil." To which Sir W. Hamilton replied as follows:-- "EDINBURGH, _Dec_. 4, 1848. "I feel deeply obliged to you for the kindness of your letter, and trust that I shall not prove wholly unworthy of the interest you take in me. There is indeed no one with whom I am acquainted whose sentiments on such matters I esteem more highly, for there is no one who, I am sure, is more earnest for the truth, and no one who pursues it with more independence and, at the same time, with greater confidence in the promised aid of God. May this promised aid be vouchsafed to me."[7] [Footnote 7: _Memoir of Sir W. Hamilton_, pp. 299-301.] CHAPTER VI THE CENTRAL PROBLEM It was confidently expected, not merely by Cairns's personal friends but by others in a much wider circle, that he would make a name for himself in the world of letters and speculative thought. It was not only the brilliance of his University career that led to this expectation, for, remarkable as that career had been, there have been many men since his time who, so far as mere prize taking is concerned, have equalled or surpassed him--men who never aroused and would not have justified any high-pitched hopes about their future. But Cairns, in addition to gaining academic distinctions, seems to have impressed his contemporaries in a quite exceptional degree with a sense of his power and promise. Professor Masson, writing of him as he was in his student days, thus describes him: "There was among us one whom we all respected in a singular degree. Tall, strong-boned, and granite-headed, he was the student whom Sir William Hamilton himself had signalised and honoured as already a sterling thinker, and the strength of whose logic, when you grappled with him in argument, seemed equalled only by the strength of his hand-grip when you met him or bade him good-bye, or by the manly integrity and nobleness of his character."[8] And again, writing of him as he was at a later date, the same critic gives this estimate of his old fellow-student's mental calibre: "I can name one former student of Sir William Hamilton's, now a minister in what would be accounted in England one of the straitest sects of Scottish Puritanism, and who has consecrated to the duties of that calling a mind among the noblest I have known and the most learned in pure philosophy. Any man who on any subject of metaphysical speculation should contend with Dr. Cairns of Berwick-on-Tweed, would have reason to know, ere he had done with him, what strength for offence and defence there may yet be in a Puritan minister's hand-grip."[9] [Footnote 8: _Macmillan's Magazine_, December 1864, p. 139.]