What is the summary of Chapter 4 of The Cay?

After being rescued from the shipwreck, Phillip finds himself lost on the ocean on a raft with Timothy.  The two talk, and Phillip, who is from Virginia, measures the preconceptions he has about Negroes against the reality of his companion.  He learns that Timothy is from the Virgin Islands, that contrary to expectations the man does not remember Africa, that he has no memory of his mother and father and does not know his age.  He is patient and gentle with Phillip, however, feeding him and making sure he stays warm during the night.

Phillip's head aches intensely from when he was hit during the shipwreck.  When the pain finally subsides, he discovers to his horror that he is blind.