4. Mechanisms used to control slaves, from Thomas Branagan, The Penitential Tyrant; or, slave trader reformed, 1807. The shackles and spurs (lower left) were intended to prevent escape; the faceguard with spiked collar (top and lower right) kept its wearer from either eating or lying down. Source: Library of Congress.

Source 4 appeared in an abolitionist work published in New York in 1807. How does that fact influence your interpretation of the images?