 Emerson never questioned the iniquity of slavery, though it was not a main item on his intellectual agenda until the eighteen forties. He refers to abolition in the “Prospects” chapter of Nature when he speaks of the “gleams of a better light” in the darkness of history and gives as examples “the abolition of the Slave-trade,” “the history of Jesus Christ,” and “the wisdom of children” (CW1:43). He condemns slavery in some of his greatest essays, “Self-Reliance” (1841), so that even if we didn’t have the anti-slavery addresses of the 1840s and 1850s, we would still have evidence both of the existence of slavery and of Emerson’s opposition to it. He praises “the bountiful cause of Abolition,” although he laments that the cause had been taken over by “angry bigots.” Later in the essay he treats abolition as one of the great causes and movements of world history, along with Christianity, the Reformation, and Methodism. In a well-known statement he writes that an “institution is the shadow of one man,” giving as examples “the Reformation, of Luther; Quakerism, of Fox; Methodism, of Wesley; Abolition of Clarkson” (CW2: 35). The unfamiliar name in this list is that of Thomas Clarkson (1760–1846), a Cambridge-educated clergyman who helped found the British Committee for the Abolition of the Slave Trade. Clarkson travelled on horseback throughout Britain, interviewing sailors who worked on slaving ships, and exhibiting such tools as manacles, thumbscews, branding irons, and other tools of the trade. His  History of the Rise, Progress, and Accomplishment of the Abolition of the African Slave Trade by the British Parliament (1808) would be a major source for Emerson’s anti-slavery addresses.