It is as though one standing beside a great water-wheel should estimate its power and rotation by measuring the width and depth of the buckets and calculating the weight of water which its thirty-two receptacles contain, saying, "at its present rate in so many seconds it will cease to move." But we take him to the water-gate, and show it wide open; to the great dam above it which contains cubic miles of water; and still beyond that to the mighty fountains bursting forth with their rush and roar from the rock-ribbed fastnesses of the eternal hills, and pouring their unfailing flood-tide down forever and ever. And we do not pause even here: we show him the vapors rising from the spent water again, condensing into clouds, pouring down in torrents of rain among the hills, and that these continuously feed the sources of the fountains, which in turn supply the wheel almost to bursting. And so it is with the glorious mechanism of the heavens. The source of solar energy is not to be found in the sun itself, but in his environment; and he himself, in all his glory, is but the king, crowned with gold, blazing with rich apparel, and scattering benefits among his satellites, not from his own private treasury, but who himself is enriched by the mighty tribute with which his willing subjects continually endow him, and to whom alone he owes all his pride and power and wealth and magnificence, and which he, in turn, so freely expends, transmuted in form alone, in the perpetual improvement and welfare of his domain. He is the faithful ruler, but not the creator; the beneficent monarch, but not the god. CHAPTER XI. THE GASEOUS NEBULÆ.