about four o'clock in the afternoon
` Here 's your money . Now listen to me ; you will know the old woman again who came to see you this morning ? ' ` Yes . ' ` To-morrow , or the day after at furthest , you will see her arrive , about four o'clock in the afternoon , on the shore opposite your island with a young girl ; the old woman will make you a signal by waving her handkerchief . ' ` Yes . ' ` How long does it take to go from the shore to your island ? ' ` Twenty good minutes . '