Our knowledge of mountains, thanks to the labours of a zealous army of workers, is now considerable. The professors of physical science have been busy making important observations on the condition of the atmosphere in the higher regions; geographers have noted their heights and mapped their leading contours. Geologists have done a vast amount of work in ascertaining the composition and arrangement of the rocks of which mountain chains are composed, in observing their peculiar structures, in recording the changes which are continually effecting their waste and decay, and thus interpreting the story of the hills as it is written in the very rocks of which they are built up. Naturalists have collected and noted the peculiar plants and animals which have their home among the hills, and so the forms of life, both animal and vegetable, which inhabit the mountains of Europe, and some other countries, are now fairly well known. The historian, the antiquary, and the student of languages have made interesting discoveries with regard to the mountain races of mankind. And only to mention this country, such writers as Scott, Wordsworth, and Ruskin have given us in verse and prose descriptions of mountain scenery which will take a permanent place in literature; while Turner, our great landscape-painter, has expressed the glories of mountain scenery in pictures which speak more eloquently than many words. Thus we see that whatever line of inquiry be chosen, our subject is full of varied interest. With regard to the characteristics of mountain races, it is not easy to say to what extent people in different parts of the world who live among mountains share the same virtues or the same failings; but the most obvious traits in the character of the mountaineer seem to be the result of his natural surroundings. Thus we find mountaineers generally endowed with hardihood, strength, and bravery. To spend one's days on the hillsides for a large part of the year, as shepherds and others do in Scotland or Wales, and to walk some miles every day in pure bracing air, must be healthy and tend to develop the muscles of the body; and so we find the highlanders of all countries are usually muscular, strong, and capable of endurance. And there can be little doubt that mountain races are kept up to a high standard of strength and endurance by a rigorous and constant weeding out of the weakly ones, especially among children. And if only the stronger live to grow up and become parents, the chances are that their children will be strong too. Thus Nature exercises a kind of "selection;" and we have consequently "the survival of the fittest." This "selection," together with the healthy lives they lead, is probably sufficient to account for their strength and hardiness.