This decay of interest in speculative thought might be attributed to the decline of mental freshness and of hospitality to new ideas which often comes with advancing years, were it not that, in his case, there was no such decline. On the contrary, as his interest in speculative thought gradually withered, his interest on the side of scholarship and linguistics became greater than ever, and his energy here was always seeking new outlets for itself. When he was nearly sixty he began the study of Assyrian. He did so in connection with his lectures on Apologetics,—because he wanted to give his class some idea of the confirmation of the Scripture records, which he believed were to be found in the cuneiform inscriptions. But ere long the study took possession of him. His letters, and the little time-table diary of his daily studies, record the hours he devoted to it. When he went to America he took his Assyrian books with him, and pored over them on the voyage whenever the Atlantic would allow him to do so. And he was fully convinced that what interested him so intensely must interest his students too. One of them, the Rev. J.H. Leckie, thus describes how he sought to make them share in his enthusiasm:—
"One day when we came down to the class, we found the blackboard covered with an Assyrian inscription written out by himself before lecture hour, and the zest, the joy with which he discoursed upon the strange figures and signs showed that, though white of hair and bent in frame, he was in the real nature of him very young. For two days he lectured on this inscription with the most assured belief that we were following every word, and there was deep regret in his face and in his voice when he said, 'And now, gentlemen, I am afraid we must return to our theology.'"[20]
Another of his students, referring to the same lectures, writes as follows:—
"It was fine, and one loves him all the more for it, but it was exasperating too, with such tremendous issues at stake in the world of living thought, to see him pounding away at those truculent old Red Indians in their barbarian original tongue. Yet I would not for much forget those days when we saw him escaping utterly from all worries and troubles and perfectly happy before a blackboard covered with amazing characters. It was pure innocent delight in a new world of knowledge, like a child's in a new story-book."
When he was sixty-three he added Arabic to his other acquirements. It is not quite clear whether he had in view any purpose in connection with his professional work beyond the desire to know the originals of all the authorities quoted in his lectures. But, when he had sufficiently mastered the language to be able to read the Koran, he knew that he had two grounds for self-congratulation, and these were sufficiently characteristic. One was that he had his revenge on Gibbon, who had described so triumphantly the career of the Saracens and who yet had not known a word of their language. The other was that he was now able to pray in Arabic for the conversion of the Mohammedans.
About the same time he began to learn Dutch. He assigned as one reason for this that he wanted to read Kuenen's works. But as the only one of these that he had was in his library already, having come to him from the effects of a deceased friend, it is possible that this was just an unconscious excuse on his part for indulging in the luxury of learning a new language—that he read Kuenen in order to learn Dutch, instead of learning Dutch in order to read Kuenen. However, his knowledge of the language enabled him to follow closely a movement which excited his interest in no common degree, viz. the secession of a large evangelical party from the rationalistic State Church of Holland, under Abraham Kuyper, the present Prime Minister of that country, and their organisation into a Free Presbyterian Church.
Other languages at which he worked during this period were Spanish, of which he acquired the rudiments during his tour in California; and Dano-Norwegian, which he picked up during a month's residence at Christiania in 1877, and furbished for a meeting of the Evangelical Alliance at Copenhagen in 1884. All this time he was pursuing his Patristic and other historical studies with unflagging vigour, always writing new lectures, always maintaining his love of abstract knowledge and his eager desire to add to his already vast stores of learning. When, a year and a half before his death, a vacancy occurred in the Church History chair in the College, he stepped into the breach and delivered a course of lectures on the Fathers, which took his class by storm.
"His manner," says one who heard these lectures, "was quite different in the Church History classroom from what it was in that of Systematic Theology. In the latter he taught like a man who felt wearied and old; but in the former he showed a surprising freshness and enthusiasm. It was delightful to see him in the Church History class forgetting age and care, and away back in spirit with Origen and his other old friends."
These lectures, while abounding in searching and masterly criticism of doctrinal views, are specially noticeable for their delineation of the living power of Christianity as exhibited in the men and the times with which they deal. This was the aspect of Christian truth which had all along attracted him. It was what had determined his choice of the ministry as the main work of his life, and in his later years it still asserted its power over him. Although he had now no longer a ministerial charge of his own, he could not separate himself from the active work of the Church—he could not withdraw from contact with the Christian life which it manifested.
During the winter months he preached a good deal in Edinburgh, especially by way of helping young or weak congregations, more than one of which he had at different times under his immediate care until they had been lifted out of the worst of their difficulties. In summer he ranged over the whole United Presbyterian Church from Shetland to Galloway, preaching to great gatherings wherever he went. In arranging these expeditions, he always gave the preference to those applications which came to him from poor, outlying, and sparsely peopled districts, where discouragements were greatest and the struggle to "maintain ordinances" was most severe. His visits helped to lift the burden from many a weary back, and never failed to leave happy and inspiring memories behind them. Among these summer engagements he always kept a place for his old congregation at Berwick, which he regularly visited in the month of June, preaching twice in the church on Sunday, and finishing the day's work by preaching again from the steps of the Town Hall in the evening. On these occasions the broad High Street, at the foot of which the Town Hall stands, was always crowded from side to side and a long way up its course, while all the windows within earshot were thrown open and filled with eager listeners.