In Emerson’s company Thoreau’s hope of becoming a poet looked not only proper but feasible. Late in 1837, at Emerson’s suggestion, he began keeping a journal that covered thousands of pages before he scrawled the final entry two months before his death. He soon polished some of his old college essays and composed new and better ones as well. He wrote some poems—a good many, in fact—for several years. A canoe trip that he and his brother John took along the Concord and Merrimack rivers in 1839 confirmed in him the opinion that he ought not be a schoolmaster but a poet of nature.

As the 1840s began, Thoreau formally took up the profession of poet. Captained by Emerson, the Transcendentalists started a magazine, The Dial. Its inaugural issue, dated July 1840, carried Thoreau’s poem “Sympathy” and his essay on the Roman poet Aulus Persius Flaccus. The Dial published more of Thoreau’s poems and then, in July 1842, the first of his outdoor essays, “Natural History of Massachusetts.” Though disguised as a book review, it showed that a nature writer of distinction was in the making. Then followed more lyrics, and fine ones, such as “To the Maiden in the East,” and another nature essay, remarkably felicitous, “A Winter Walk.” The Dial ceased publication with the April 1844 issue, having published a richer variety of Thoreau’s writing than any other magazine ever would.

In 1840 Thoreau fell in love with and proposed marriage to an attractive visitor to Concord named Ellen Sewall. She accepted his proposal but then immediately broke off the engagement at the insistence of her parents. He remained a bachelor for life. During two periods, 1841–43 and 1847–48, he stayed mostly at the Emersons’ house. In spite of Emerson’s hospitality and friendship, however, Thoreau grew restless; his condition was accentuated by grief over the death of his brother John, who died of tetanus in January 1842 after cutting his finger. Later that year Thoreau became a tutor in the Staten Island household of Emerson’s brother, William, while trying to cultivate the New York literary market. Thoreau’s literary activities went indifferently, however, and the effort to conquer New York failed. Confirmed in his distaste for city life and disappointed by his lack of success, he returned to Concord in late 1843.