Now in this process of the interpenetration of matter by spirit there must be a certain periodicity, if it is a constant process and not one accomplished once and for all time in the very beginnings of the world. This rhythmical action, which is exemplified by every phenomenon of nature, the vibratory process of light, sound, heat, electricity, the pulsation of the heart, the motion of the tides, has never escaped the observation even of primitive peoples, and always attempts have been made to determine its periodicity. May it not be infinitely complex, as the ripple rises on the wave that lifts on the swell of the underlying tide? Certainly we are now being forced back to a new consideration of this periodical beat, in history at least, for now that our own era, which came in by the power of the Renaissance and the Reformation and received its final energizing force through the revolutions of the eighteenth century and the industrial revolution of the nineteenth, is so manifestly coming to its end, we look backward for precedents for this unexpected debacle and lo, they appear every five hundred years back as far as history records. 500 B.C., Anno Domini; 500 A.D., 1000 A.D., and 1500 A.D. are all, to the point of very clear approximation, nodal points, where the curve of the preceding five centuries, having achieved its crest, curves downward, and in its fall meets the curve of rising energy that is to condition the ensuing era. The next nodal point, calculated on this basis, comes about the year 2000. Are we not justified, in plotting our trajectory of modernism, in placing the crest in the year 1914, and in tracing the line of fall from that moment?