Is the great Book of Nature--the world we live in--a closed or open book to Man? On this question all have thought often,--and many have written much,--students--men of science--religious teachers--poets, and philosophers. We ask this question of ourselves variously circumstanced, and under various impulses. We ask it if, like Æschylus' watchman, we contemplate "The congress of the nightly stars Bright potentates, set proudly in the sky." Or when we sail upon a sea made solemn by its vastness, dying in far distance, with no boundary except itself, as each swelling wave rises against the sky. We ask it, on some stately mountain top looking down over light and shadow,--over the rest and the motion of the landscape. More earnestly still, perhaps, while from the depth of a twilight valley we admire the sunset lingering upon inapproachable alpine snows;--rosy heights unveiling their loveliness, yet soon to be hidden till the Light of this lower world shall shine afresh amongst their clefts and pinnacles. And who is not in earnest, as sunset and sunrise remind him how the majestic clock of Time moves on? Yonder glorious luminary has warmed with form and life countless organisms, scattered over mountain summits, in ocean depths, through wild savannahs and forests;--organisms throughout regions of earth, water, air, so remote and inaccessible that their wonderful excellence of beauty has never been beheld by Man's perishable eye. Knowing, as we cannot but know, how soon our own eyelids must close beneath the sun, we yearn within our soul, longing for a truer insight into the great Universe above and beyond us; and for a firmer feeling that we ourselves are an imperishable part of it. Somewhere in this Universe, must surely be contained things brighter and better than those we now possess. Else, why is it clothed so lavishly with half-revealed charms, adapted to touch our most delicate sympathies, to win us from our worse selves, and allure us on like willing captives to its loveliness? Awakened in our senses, awakened in our souls, we desire to know, to feel, and to attain;--these three impulses become our fixed and enduring aspirations. But, how? We all remember that Undine sought a soul and found a sorrow;--a sorrow the more intolerable, because through its burden she first realized her hard-earned dower of coveted immortality. Yet, as she truly says, every creature cannot but strive after that which is naturally higher than itself. _One_ secret of progress we soon discover. What Nature can give us depends on what she can tell us. And here is a prevailing motive for the endeavour to unclose fair Nature's book.