By this ray of light, such as it was, he long was enabled to dominate all that portion of the unknown which he declined to term fatality. To us who come after him, the portion of the unknown that he controlled may well seem insufficient, if surveyed from an eminence, and yet it was truly one of the vastest that the eye of man has ever embraced. Through its means every action of his was accomplished, for evil or good. This is not the place to judge him, or even to wonder whether the happiness of a century might not have been better served had he allowed events to guide him; what we are considering here is the docility of the unknown. For us, with our humbler destinies, the problem still is the same, and the principle too; the principle being that of Goethe: "to stand on the outermost limit of the conceivable; but never to overstep this line, for beyond it begins at once the land of chimeras, the phantoms and mists of which are fraught with danger to the mind." It is only when the intervention of the mysterious, invisible, or irresistible becomes strikingly real, actually perceptible, intelligent, and moral, that we are entitled to yield or lay down our arms, meekly accepting the inactive silence they bring; but their intervention, within these limits, is rarer than one imagines. Let us recognise that mystery of this kind exists; but, until it reveal itself, we have not the right to halt, or relax our efforts; not the right to cast down our eyes in submission, or resign ourselves to silence. III THE KINGDOM OF MATTER 1