Though centuries have passed, nature is so reticent that man is still uncertain whether a diet of grain or a diet of flesh makes the ruddier countenance. Also it is a matter of doubt whether some young Lincoln can best be educated in the university of rail-splitting or in a modern college and library; whether poverty or wealth does the more to foster the poetic spirit of Burns or the philosophic temper of Bach. In the beautiful temple of Jerusalem there was an outer wall, an inner court, "a holy place," and afar-hidden within, "a place most holy." Thus nature conceals her secrets behind high walls and doors, and God also hath made thick the clouds that surround the divine throne.
Marvelous, indeed, the skill with which nature conceals secrets numberless and great in caskets small and mean. She hides a habitable world in a swirling fire-mist. A magician, she hides a charter oak and acre-covering boughs within an acorn's shell. She takes a lump of mud to hold the outlines of a beauteous vase. Beneath the flesh-bands of a little babe she secretes the strength of a giant, the wisdom of a sage and seer. A glorious statue slumbers in every block of marble; divine eloquence sleeps in every pair of human lips; lustrous beauty is for every brush and canvas; unseen tools and forces are all about inventors, but they who wrest these secrets from nature must "work like slaves, fight like gladiators, die like martyrs."
For nature dwells behind adamantine walls, and the inventor must capture the fortress with naked fists. In the physical realm burglars laugh at bolts and bars behind which merchants hide their gold and gems. Yet it took Ptolemy and Newton 2,000 years to pick the lock of the casket in which was hidden the secret of the law of gravity. Four centuries ago, skirting the edge of this new continent, neither Columbus nor Cabot knew what vast stretches of valley, plain, and mountain lay beyond the horizon.
If once a continent was the terra incognita, now, under the microscope, a drop of water takes on the dimensions of a world, with horizons beyond which man's intellect may not pass. Exploring the raindrop with his magnifying-glass, the scientist marvels at the myriad beings moving through the watery world. For the teardrop on the cheek of the child, not less than the star riding through God's sky, is surrounded with mystery, and has its unexplored remainder. Expecting openness from nature, man finds clouds and concealment. He hears a whisper where he listens for the full thunder of God's voice to roll along the horizon of time.