The first fact of importance about Thoreau is the fact that he wrote day after day, seldom a day omitted for years, the 6,811 closely printed pages of his journal, every part done with thoroughness and finish, with no dream that it ever was to be published. It is a fact enormously significant; it reveals to us the naked man; it furnishes a basis for all constructive criticism. "My journal," he wrote November 16, 1850, "should be the record of my love. I would write in it only of the things I love, my affection for an aspect of the world, what I love to think of." And again, "Who keeps a journal is purveyor to the gods." And still again, February 8, 1841, "My journal is that of me which would else spill over and run to waste, gleanings from the field which in action I reap. I must not live for it, but, in it, for the gods. They are my correspondents, to whom daily I send off this sheet, post-paid. I am clerk in their counting house, and at evening transfer the account from day-book to ledger." He was not a poser for effect, for it is impossible for one to pose throughout 6,811 printed pages wrought for no eyes save his own and the gods. His power came rather from the fact that he did not pose; that he wrote spontaneously for the sheer love of the writing. "I think," he declares in one place, "that the one word that will explain the Shakespeare miracle is unconsciousness." The word explains also Thoreau. Again he adds, "There probably has been no more conscious age than the present." The sentence is a key: in a conscious age, a classical age building on books, watchful of conventions and precedents, Thoreau stood true only to himself and Nature. Between him and the school of Taylor and Stoddard there was the whole diameter. He was affected only by the real, by experience, by the testimony of his own soul. "The forcible writer," he wrote February 3, 1852, "stands boldly behind his words with his experience. He does not make books out of books, but he has been there in person."

In his nature observations Thoreau was not a scientist. It was not his object to collect endless data for the purpose of arriving at laws and generalizations. He approached Nature rather as a poet. There was in him an innate love for the wild and elemental. He had, moreover, a passion for transcending, or peering beyond, those bounds of ordinary experience and capturing the half-divined secrets that Nature so jealously guards. His attitude was one of perpetual wonder, that wonder of the child which has produced the mythology of the race. Always was he seeking to catch Nature for an instant off her guard. His eyes were on the strain for the unseen, his ears for the unheard.

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:

Is not the midnight like Central Africa to most of us? Are we not tempted to explore it—to penetrate to the shores of its lake Tchad, and discover the sources of the Nile, perchance the Mountains of the Moon? Who knows what fertility and beauty, moral and natural, are there to be found? In the Mountains of the Moon, in the Central Africa of the night, there is where all Niles have their hidden heads.

It was to discover these Mountains of the Moon, these mysterious sources of the Nile, forever so far away and yet forever so near, that Thoreau went to Nature. He went not to gather and to classify facts; he went to satisfy his soul. Burroughs is inclined to wonder and even laugh because of the many times he speaks of hearing the voice of unknown birds. To Burroughs the forest contained no unknown birds; to Thoreau the forest was valuable only because it did contain unknown birds. His straining for hidden melodies, his striving for deeper meanings, his dreaming of Mountains of the Moon that might become visible at any moment just beyond the horizon—it is in these things that he differs from all other nature writers. He was not a reporter; he was a prophet. "My profession is always to be on the alert, to find God in nature, to know His lurking places, to attend all the oratorios, the operas in nature. Shall I not have words as fresh as my thought? Shall I use any other man's word?"

To him Nature was of value only as it furnished message for humanity. "A fact," he declared, "must be the vehicle of some humanity in order to interest us." He went to Nature for tonic, not for fact; he sought only truth and freedom and spontaneousness of soul. He had no desire to write a botany, or an ornithology; rather would he learn of Nature the fundamentals of human living. "I went into the woods because I wished to live deliberately, to front only the essential facts of life, and see if I could not learn what it had to teach, and not, when I came to die, discover that I had not lived." Burroughs went into the woods to know and to make others to know, Thoreau went in to think and to feel; Burroughs was a naturalist, Thoreau a supernaturalist.