THE invitation to give thought to the conservation of resources that affect our future, appeals to me with almost personal force, for my studies of the past decade have led to the belief that the era of the earth's future habitability is vastly greater than we have been wont to think. We have grown up in the belief that the earth sprang from chaos at the opening of our era and is plunging on to catastrophe or to a final winter in the near future. Quite at variance with this, I have come to believe that the earth arose from a regenerative process and that it offers a fair prospect of fitness for habitation for tens of millions of years to come. If this be true, it is eminently fit that our race should give a due measure of thought to the ulterior effects of its actions.
It is one of the latest conceptions of geology that climatic conditions have been of the same order as at present from early eras, in the large view, in spite of some notable variations, and that this uniformity is the result of a profound regulative system which has sufficed to keep the temperatures of the earth's surface and the constitution of the earth's atmosphere within the narrow range congenial to life for many millions of years. As a result there has been no break in the continuity of land life since it came into being eras ago. It appears, further, that the sources of supply of the vital elements are still adequate, and are likely to be so for long ages, that the regulative system is still in effective control, and that a vast future of habitability may fairly be predicted, subject only to some contingencies of collision or disturbing approach of celestial bodies. Whether you are prepared to accept so large a view of the habitable future or not, I trust you will