Time, abstractedly considered as what in truth it is,--a portion of the vast ocean of eternity, a river flowing from the sea and flowing to the sea, a channel leading from deep to deep, through shores on which the races of the world are permitted to build for awhile, until the great waters shall once more cover all, and time, _as_ time, "shall be no more,"--must long have defied the skill of man to map out its surface, and write his memorials upon its impalpable bosom. The thousand keels that sweep over the visible waters of the world leave on their face traces of their passage more legible and enduring than do the generations of men as they come and go on that viewless and voiceless stream. The ingenuity which has taught man to lay down the plan of the material ocean, to assign to each spot on its uniform surface its positive whereabout and actual relation, and by a series of imaginary lines and figures to steer his way across its pathless solitudes with a knowledge as certain as that which guides him amidst the substantive and distinctive features of the solid earth, is scarcely more admirable than that which, by a similar device, has enabled him to measure out the expanse of the silent river, to cover, as it were, its surface with a crowd of imaginary latitudes and longitudes intersecting each other at all points, and to ascertain at any moment, by observation, his relative position on the great stream of time. How long the unaided genius of man might have been ere it could have fallen upon a scheme for the one achievement or the other, if left to struggle with its own resources and unassisted by hints from without, we need not conjecture. But in each case the solution of the problem was suggested to him, as the materials for working it are still furnished, by the finger of God himself. The great architect of the universe hath planted in its frame all necessary models and materials for the guidance and use of its human inhabitants, leaving them to the exercise of those powers and capacities with which they have been furnished to improve the lessons and apply the examples thus conveyed. In each of the cases of which we have spoken, the constellations which surround the world and "are the poetry of heaven" have been the sources of the inspiration, as they are still the lights by which that inspiration works. The hand that fashioned the "two great lights," and appointed to them their courses, and gave them to be "for signs and for seasons and for days and years," pointed out to man how he might, by the observation of their revolutions, direct his course along the unbroken stream of time or count its waves as they flowed silently and ceaselessly away. The sun and moon were the ancient and at first the only measures of time, as they are the essential foundations of all the modes by which man measures it now; and in the order of the world's architecture, the "watches of the element" which guide us yet were framed and "set in the