Darwin and FitzRoy shared a small cabin at sea for five years. Darwin's nickname aboard ship was "Philosopher." FitzRoy was noted for his qualities as a commander but also for his temper: when coming on watch, the relieving officers were accustomed to asking "if much hot coffee had been served?" In one incident, FitzRoy, an advocate of the civilizing effects of slavery, described to Darwin how the owner of a great plantation had called his slaves around him and asked if they wished to be free. They replied No. Darwin demanded of FitzRoy ("perhaps with a sneer") if the Captain thought the word of a slave in the presence of his master were worth anything. Affronted, FitzRoy ordered Darwin to leave his cabin, but shortly thereafter invited him back.