But in the same sense in which God is unknowable, all the most important realities with which we deal are also beyond our comprehension. We do not know what electricity is, what matter is, what life is. Ether is utterly beyond the reach of our definitions, and an English scientist calls it "unknown, impalpable, the necessary condition of scientific thought." As for the constituent elements of the material world, we are told that atoms are so infinitesimally minute as to be indivisible, and yet that an "electron ranges about in the atom as a mouse might in a cathedral." The plain fact is that in any realm, human knowledge soon runs off into an unknown region where it deals with invisible realities, which it cannot define, but on which life is based. While therefore we do not know what electricity, ether, electrons, and life itself are, we do know them well _in their relationship with our needs_. So we may know God. Deep beyond deep in him will be past our fathoming, but what God means in his relationships with our lives we may know gloriously. _O Thou who transcendest all thought of Thee as the heavens are higher than the earth; we acknowledge that we cannot search Thee out to perfection, but we thank Thee that Thou, the Invisible, comest to us in the things that are seen; that Thy exceeding glory is shadowed in the flower that blooms for a day, in the light that fades; that Thine infinite love has been incarnate in lowly human life; and that Thy presence surrounds all our ignorance, Thy holiness our sin, Thy peace our unrest._ _Give us that lowly heart which is the only temple that can contain the infinite. Save us from the presumption that prides itself on a knowledge which is not ours, and from the hypocrisy and carelessness which professes an ignorance which Thy manifestation has made for ever impossible. Save us from calling ourselves by a name that Thou alone canst wear, and from despising the image of Thyself Thou hast formed us to bear, and grant that knowledge of Thee revealed in Jesus Christ which is our eternal life. Amen._--W. E. Orchard. Fifth Week, Fourth Day