eight o'clock
He just kept scowling , and got up from the table and went off by himself . But he did n't go out to the observatory , as he most generally does . He went into the library and shut the door . He was there when the telephone message came at eight o'clock . And what do you think ? He 'd _ forgotten _ he was going to speak before the College Astronomy Club that evening ! Forgotten his old stars for once .