the collection grow with unreasonable rapidity. But there is reason to believe that his early interest in the rocks was not confined to glacial phenomena, but was disseminated among a variety of geological subjects; and it seems probable that the concentration of attention, throughout long years, on the Ice Age was largely due to the effect of his first work on the Survey, and to the flood of pleasurable emotion with which that work was accompanied. But it must not be supposed that his work, even in the early years, was confined to the mapping of the superficial deposits. So early as 1863 he was already doing solid geology, and thereafter went on with the mapping of solid and superficial deposits at the same time. But while he did much good work quite apart from glacial questions, and was interested in many kinds of geological problems, it was the history of the Ice Cap of Europe which especially appealed to him. His holidays--brief in early days--were devoted to the study of glacial phenomena outside his own region. His leisure hours, spent by some of his colleagues in fishing or other forms of sport, or in visiting, were largely devoted to keeping himself abreast of the literature of the subject; and this was also one of the motives which led him to study languages so assiduously, with the result that he was able to make first-hand acquaintance with the papers of all the continental geologists who wrote on his own subject. If, however, throughout his long life his geological first love commanded his unswerving devotion, it was not because the charms of other paths did not appeal to him. Some of the letters speak of an ardent desire, apparently never gratified, to deal thoroughly with Carboniferous problems, to which his attention was drawn during his prolonged and toilsome mapping of the Lanarkshire coalfield; and in an interesting letter to the writer, which dates from the early part of 1909, he speaks of other questions which had also always attracted him. Some passages from this letter may be quoted:--