anchor: At 4 o'clock, Mrs. Inglethorp quarrels with her son, and threatens to denounce him to his wife ”who, by the way, overheard the greater part of the conversation. 
positive: At 4 o'clock, Mrs. Inglethorp has an argument with her son.
negative: At 4 o'clock, Mrs. Inglethorp listens to her son play the piano for her.