There never was a time when man had so complete possession of the planet which he inhabits as the present. Much of the globe has yet to be explored; but how much is familiar to us that was comparatively unknown even at the beginning of the present century. How thoroughly during that period have we acclimated many of the plants of distant lands, which are now the common beauties of our gardens and greenhouses. There are thousands of timber-trees coming to rapid maturity in our parks and pleasure-grounds which thirty years ago grew only in the solitudes of California and Australia. One enterprising man, James Douglas, whose father was a working mason at Scone, bestowed upon this country, about twenty-five years ago, two hundred new species of plants which are now of common culture, and he gave us a tree of the pine-tribe, called after his name, which will in all probability become one of the most valuable of our timbers, from its strength, its rapid growth, and its enormous size. What impelled James Douglas, and hundreds of other travellers of a similar character, to encounter the perils of travel in desert regions, but the abstract love of science, which made them naturalists in their closets before they were explorers and discoverers? We are familiar with the name of Linnæus, and the Linnean system of botany; and some may think that this great naturalist was not doing much for knowledge when he classified and arranged what we call the vegetable kingdom. When very young, Linnæus underwent many hardships in travelling through Lapland, in search of plants. So far, some may say, he was well employed. He was equally well employed when he made such an inventory, to use a familiar term, of all the known plants of his time, as would enable succeeding naturalists to know a distinct species from an accidental variety, and to give a precision to all future botanical investigation. Other naturalists have produced other systems, which may be more simple and convenient; but the impulse which Linnæus gave to botanical discovery, and thence to the increase of the vegetable wealth of Europe, can never be too highly appreciated.