This was the work of a Reindeer Man or Cromagnard, in the Upper or Post-Glacial Pleistocene, perhaps 25,000 years ago. Firelight must have been used in making these cave drawings and engravings.] Factors in Human Progress Many, we believe, were the gains that rewarded the arboreal apprenticeship of man's ancestors. Many, likewise, were the results of leaving the trees and coming down to the solid earth--a transition which marked the emergence of more than tentative men. What great steps followed? Some of the greatest were--the working out of a spoken language and of external methods of registration; the invention of tools; the discovery of the use of fire; the utilisation of iron and other metals; the taming of wild animals such as dog and sheep, horses and cattle; the cultivation of wild plants such as wheat and rice; and the irrigation of fields. All through the ages necessity has been the mother of invention and curiosity its father; but perhaps we miss the heart of the matter if we forget the importance of some leisure time--wherein to observe and think. If our earth had been so clouded that the stars were hidden from men's eyes the whole history of our race would have been different. For it was through his leisure-time observations of the stars that early man discovered the regularity of the year and got his fundamental impressions of the order of Nature--on which all his science is founded. If we are to think clearly of the factors of human progress we must recall the three great biological ideas--the living organism, its environment, and its functioning. For man these mean (1) the living creature, the outcome of parents and ancestors, a fresh expression of a bodily and mental inheritance; (2) the surroundings, including climate and soil, the plants and animals these allow; and (3) the activities of all sorts, occupations and habits, all the actions and reactions between man and his milieu. In short, we have to deal with FOLK, PLACE, WORK; the _Famille_, _Lieu_, _Travail_ of the LePlay school. As to FOLK, human progress depends on intrinsic racial qualities--notably health and vigour of body, clearness and alertness of mind, and an indispensable sociality. The most powerful factors in the world are clear ideas in the minds of energetic men of good will. The differences in bodily and mental health which mark races, and stocks within a people, just as they mark individuals, are themselves traceable back to germinal variations or mutations, and to the kind of sifting to which the race or stock has been subjected. Easygoing conditions are not only without stimulus to new departures, they are without the sifting which progress demands.