if the ends we desire are to be attained. More generally expressed the continuity of history is the continuity of matter. It comprises in sum the structure to which every movement in time is subject. It makes up what we call the laws of nature conformably to which whatever is done must be done. But in itself it is inert and impotent. Activity of some sort must penetrate it, if there is to be anything effected. And what is effected reveals, when experimentally understood, the laws as limitations within which the control of any movement is possible. A wall is built by laying stone on stone. It may be torn down and built again, or left a ruin. The placing or overthrow of every stone occurs as just that event but once, never to return, but the stones, though chiseled or worn in the handling, remain constant material for constant use. The result is a wall or a ruin, both of which illustrate the law of gravitation, but neither of which was produced by that law. That is what history is like. It is an activity which transforms the materials of the world without destroying them, and transforms them subject to laws of their own. The world is thus ever new, but never lawless. It is always fresh and always old. The present is, as Francis Bacon said, its real antiquity. Time is thus the arch-conservative and the arch-radical. Forever it revises its inheritance, but it is never quit of it. Man's inheritance comprises both what he has derived from his ancestors, and also the world bequeathed to him from day to day. This material he uses with some knowledge of its laws, and with the conscious desire to convert it to his own ends. The kinds of progress he can make are thus relevant to the purposes he sets before him. Since the satisfaction of his physical needs and the desire of comfortable living require some mastery of physical resources, his progress can naturally be measured by the degree of success he makes in providing for satisfactions of this kind. Such progress is material progress, and its standards are economy and efficiency, or the attainment of the maximum result with the minimum of effort. This kind of progress is very diversified, embracing all the economic concerns of life, and much of society and the arts. But material prosperity is provisional. To be well-housed, well-fed, well-clothed, and even to have friends and the opportunity for unlimited amusement, these things have never been permanently regarded as defining human happiness to the full. Having these things man is still curious to know what he will do. Material progress indicates mastery of the necessities of his existence in order that he may then be free to act. If no free act follows upon such mastery, life loses its savor, and pleasures grow stale. Material progress would thus seem to be a preliminary to living well, but would not be living well itself. For man would be in a sorry plight if he succeeded in mastering the physical