imagination, keeping within the limits of reason, we can predict the rate of progress will be continuous. It is quite conceivable that before this generation is passed we shall plough with power generated by the tides and transmitted by wireless processes, and that radium will be harnessed so that its incalculable energy can be used. With the tremendous increase in power the surface of the earth can be enlarged indefinitely. Why should not the plains of Europe and America be set on edge, or why should not artificial heat and light make possible several layers of productive soil, and certainly it can be employed all the year round! Already sanitation and invention are making possible the exploitation of the tropics, the really productive regions of the earth which hitherto have been undeveloped. Men can soon work where they can not live continuously because they can commute in airships and change climatic conditions daily.
In the light of these facts and fancies let us consider the validity of Malthus'"s three principles:
1. "Population is necessarily limited by the means of subsistence." This is more imaginative than dangerous, for, since "means of subsistence" is psychological as well as physical, it can not become a mathematical term. Nowadays our magazines are telling us that consumption of one half or one third of the "means of subsistence" would add greatly to our efficiency. I myself have made a definite reduction in the amount of food consumed and thereby multiplied my efficiency. Furthermore, it is undoubted that the science of nutrition is going to add many units to the food supply by subtracting the injurious, the wasted, and the unnecessary. This is the prospect before us, but in the meantime, with all the natural forces for multiplication of population active, nevertheless the means of subsistence has increased far beyond any proportions that have before prevailed. There is not the slightest evidence to-day that means of subsistence is directly effecting the increase in population.
2. "Population invariably increases where the means of subsistence increases, unless prevented by very powerful and obvious checks." This is so untrue to-day that it is not open to argument. In fact, the portion of population having the greatest means of subsistence is standing still while the poorest furnishes the greatest increase. To be sure, the standard of life may be the line at which the force of the means of subsistence is defined, but this is an artificial line. The rate of increase is not lessened by any powerful and obvious check, and it is not beginning to keep up with the rate of increase of the means of subsistence. There never was a time when the world was as well fed as at the present.
3. "These checks and the checks which repress the superior power of population and keep its effects on a level with the means of subsistence are all resolvable into moral restraint, vice and misery." Professor