Two Years Before the Mast, a novel published in 1840, was among a "select company" that included Ralph Waldo Emerson, James Russell Lowell, A. Bronson Alcott, and a young Franklin Benjamin Sanborn. Presumably with restraint, he concluded, "It was very agreeable."
Of Emerson, Dana recorded he was "a gentleman, never bores or preaches or dictates... and has even skill and tact in managing his conversation." He said the same of Alcott and noted, "it is quite surprising to see these transcendentalists appearing well as men of the world."
Perhaps more interesting, however, is that all these gentlemen were anti-slavery men. Dana himself had only recently defended the fugitive Anthony Burns in a trial meant to challenge the Fugitive Slave Act of 1850. Dana also paired with Robert Morris, an African-American lawyer; their efforts, however, were unsuccessful.
Emerson was a strong voice against slavery in the 1850s through his speeches; Lowell used his pen. For a short time, he edited an apolitionist newspaper in Pennsylvania but focused his poetic voice on the cause in poems like "The Present Crisis" and "On the Capture of Fugitive Slaves Near Washington." Alcott hosted at least one man escaped from enslavement in his Concord home years earlier and was part of a crowd that attempted to free Anthony Burns from a Boston courthouse. Dana referred to the young Sanborn, then a Harvard student, as "clever and promising." Only a few years later, Sanborn funded the radical abolitionist John Brown in his raid on Harper's Ferry as a member of the so-called "Secret Six."