twelve o'clock
The curve sprawled across the ruled surface of the sheet by the automatic registering-needle was irregular , showing the ups and downs of the current , rising sharply from sundown and gradually declining after nine o'clock , as the lights went out . Somewhere between eleven and twelve o'clock , however , the irregular fall of the curve was broken by a quite noticeable upward twist . Craig asked the men if that usually happened . They were quite sure that the curve as a rule went gradually down until twelve o'clock , when the power was shut off . But they did not see anything remarkable in it . `` Oh , I suppose some of the big houses had guests , '' volunteered the foreman , `` and just to show off the place perhaps they turned on all the lights . I do n't know , sir , what it was , but it could n't have been a heavy drain , or we would have noticed it at the time , and the lights would all have been dim . ''