great revolution by so many other able thinkers and workers, whose names will never survive into future ages.
Every now and then a great crisis occurs in the world's history when some new advance, rendered inevitable by the slow growth of the past, halts for a moment on the threshold of realization. A genius is needed to make the advance; but the genius is always then and there forthcoming from the vast reservoir of potential greatness forever present in all civilized countries. It is the noble chance that brings forth the noble knight: the men lucky enough to take the tide at its flood, lucky enough to reach maturity at the very moment of the turn, achieve a visible success perhaps somewhat disproportioned even to their real and undoubted merit. Or rather, they throw unduly into the shade the men who precede and the men who come after them. There are moments when good workers can not fail to obtain wonderful results, because those results are then and there almost forced upon them by the circumstances of science. There are moments when good men must almost of necessity become hewers of wood and drawers of water for the architectonic generation that will come after them, because the last generation has built up all the materials then available, and new stores must needs be collected before another story can possibly be added to the whole vast fabric of scientific thought. Every mighty outburst is followed close by an apparent lull, a lull during which the forces at work are expending themselves rather upon preparation than upon actual performance, upon providing fresh facts and hypotheses and suggestions rather than upon co-ordinating and interpreting the old ones.
Hence it may often happen that certain names, popularly regarded as small, may really belong to greater individualities and greater intellects than certain other names of critical and, so to speak, nodal interest. The man who comes at the exact turning-point performs in one sense a greater work than the man, however able, who chances to light upon one of the ebb-tides or intervening periods. Geology supplies us in our own day with an excellent example. Lyell's name will always be held to typify the evolutionary impulse in geology, as Darwin's does in biology, Spencer's in psychology, and Laplace's in astronomy. But of these four central names, Lyell's stands distinctly on a much lower mental level than the remaining three. On the other hand, we have now among us a geologist of the very highest ability, a man who has devoted to his chosen science a breadth and profoundness of cosmical grasp never before associated with it—I mean, of course, Archibald Geikie. It is impossible for any competent critic to look at Geikie's "Text-Book of Geology" by the side of Lyell's "Principles and Elements" without immediately recognizing the immense difference of mental stature between the two men. I do
