Sketches of Portuguese life, manners, costume, and character (1826). A very interesting read. The illustrations form the basis for the narratives. This for example, accompanies the last illustration shown here:
I was in one of these stables, when a slave merchant from the latter place came in and enquired what sort of stuff was on sale. The shopman, anxious to transact business immediately, took a sack of arrow-root (farinha de pao) and placing about a dozen little handfuls of it here and there on the ground, made signal to the slaves to come and eat, just as we see done by a servant to call together the fowls in a poultry yard. The slaves made a rush at the little heaps, and squatting down on their haunches, just like monkeys, began to eat with avidity.It then goes on to relate several anecdotes and observations regarding the slave trade in this region.