He was much gratified by its success, for he felt that he had done something to stimulate accurate field surveying by students of geology, and field work he always considered the most educative part of geological training. Here we may mention also his contributions to _Chambers’s Encyclopædia_, for which he wrote many of the geological articles. In 1875 he had prepared a small Elementary Manual for the well-known Edinburgh firm of publishers, and as successive editions of the _Encyclopædia_ were printed he continued to revise his geological articles, so that he had a continuous connection with Messrs Chambers lasting over forty years. * * * * * His work as a geographer next claims our attention. The fields of geological research which he especially cultivated have a very close connection with geographical science. In the Scottish Geographical Society, as already stated, he took a deep interest from the start. For many years his face was a familiar one on the platform at the lectures delivered by eminent geographers and distinguished travellers in Edinburgh, and as these lectures are always very well attended, probably his connection with the Society made him better known to the general public than any other of his numerous activities. These functions also brought him into contact with many explorers and scientists who came to Edinburgh to lecture, and were the source of many friendships which he valued highly. During the latter years of his life the Geographical Society claimed almost as much of his attention as his academic duties, and as he was fortunately assisted by very competent lecturers in the University, he could spare the time required to fulfil both functions. His studies in geography were always in those fields which form the border-land between geology and geography. The history of the development of scenery and of earth-forms in general, and the relation between geological structure and geographical configuration, were favourite subjects for his pen. In this he was a true follower of Playfair. He delighted also to prepare short notices for the Society’s magazine, describing the results of recent work on prehistoric man, on changes of climate in recent geological periods, and the action of ice in the production of surface features. The magazine proved a useful vehicle for conveying to the public the results of his wide reading on topics such as these. Many of the articles which first appeared in its pages were subsequently issued in book form, or were used in the preparation of the third edition of _The Great Ice Age_, and the other scientific treatises which he produced.