For the reasons above given, we must regard the hypothesis of the great French astronomer as a wonderful approximation to the grand and simple plan of the construction of our system as revealed in Scripture. Nor must we omit to notice that the telescope and the spectroscope reveal to us in the heavens gaseous nebular bodies which may well be new systems in progress of formation, and in which the Creator is even now dividing the light from the darkness. Still another thought in connection with this subject is that the theory of a condensing system affords a measure of the aggregate time occupied in the work of creation. Sir William Thomson's well-known calculations give us one hundred millions of years as the possible age of the earth as a planetary globe; but calculations of the sun's heat as produced by gravitation alone would give a much less time. We have, however, a right to assume an original heated condition of the vaporous mass from which the sun was formed. Still the date above given would seem to be a maximum rather than a minimum age for the solar system. "God saw the light that it was good," though it illuminated but a waste of lifeless waters. It was good because beautiful in itself, and because God saw it in its relations to long trains of processes and wonderful organic structures on which it was to act as a vivifying agency. Throughout the Scriptures light is not only good, but an emblem of higher good. In Psalm civ. God is represented as "clothing himself with light as with a garment;" and in many other parts of these exquisite lyrics we have similar figures. "The Lord is my light and salvation;" "Lift up the light of thy countenance upon me;" "The entrance of thy law giveth light;" "The path of the just is as a shining light." And the great spiritual Light of the world, the "only begotten of the Father," the mediator alike in creation and redemption, is himself the "Sun of Righteousness." Perhaps the noblest Scripture passage relating to the blessing of light is one in the address of Jehovah to Job, which is unfortunately so imperfectly translated in the English version as to be almost unintelligible: "Hast thou in thy lifetime given law to the morning, Or caused the dawn to know its place, That it may enclose the horizon in its grasp, And chase the robbers before it: It rolls along as the seal over the clay, Causing all things to stand forth in gorgeous apparel."[46] Job xxxviii., 12. The concluding words, "Day one," bring us to the consideration of one of the most difficult problems in this history, and one on which its significance in a great measure depends--the meaning of the word _day_, and the length of the days of creation.