I was always conscious of sounds in Nature which my ears could not hear, that I caught but a prelude to a strain. She always retreats as I advance. Away behind and behind is she and her meaning. Will not this faith and expectation make itself ears at length? I never saw to the end, nor heard to the end, but the best part was unseen and unheard.--February 21, 1842. Nature so absorbed him that he lived constantly in an eager, expectant atmosphere. "I am excited by this wonderful air," he writes, "and go, listening for the note of the bluebird or other comer." It was not what he saw in Nature that was important; it was what he felt. "A man has not seen a thing who has not felt it." He took stock of his sensations like a miser. "As I came home through the woods with my string of fish, trailing my pole, it being now quite dark, I caught a glimpse of a woodchuck stealing across my path, and felt a strange thrill of savage delight, and was strongly tempted to seize and devour him raw; not that I was hungry then, except for that wildness which he represented." It was by this watchfulness for the elemental, this constant scrutiny of instincts and savage outcroppings, that he sought to master the secret that baffled him. He would keep himself constantly in key, constantly sensitive to every fleeting glimpse of harmony that Nature might vouchsafe him. Nature stirred him always on the side of the imagination. He loved Indian arrow-heads, for they were fragments of a mysterious past; he loved twilight effects and midnight walks, for the mystery of night challenged him and brought him nearer to the cosmic and the infinite: I have returned to the woods and ... spent the hours of midnight fishing from a boat by moonlight, serenaded by owls and foxes, and hearing, from time to time, the creaking note of some unknown bird close at hand. These experiences were very memorable and valuable to me--anchored in forty feet of water, and twenty or thirty rods from the shore ... communicating by a long flaxen line with mysterious nocturnal fishes which had their dwelling forty feet below, or sometimes dragging sixty feet of line about the pond as I drifted in the gentle night breeze, now and then feeling a slight vibration along it, indicative of some life prowling about its extremity, of dull uncertain blundering purpose there.... It was very queer, especially in dark nights, when your thoughts had wandered to vast and cosmogonal themes in other spheres, to feel this faint jerk which came ... to link you to Nature again. Burroughs, like most scientists, slept at night. His observations were made by day: there is hardly a night scene in all his works; but Thoreau abounds in night scenes as much even as Novalis or Longfellow. He was at heart a mystic and he viewed Nature always from mystic standpoints. In "Night and Moonlight" he writes: