five o'clock
`` Then , if they have a base anywhere along the coast we ought to be there before tomorrow at this time ? '' ventured Alfred . `` That is exactly what I mean , '' answered the captain . There was a steady pulsation of the engines during the entire afternoon without cessation until five o'clock , when the submarine submerged and continued under water for an hour . The three captives had now learned a great many of the manoeuvers incident to the diving operations , the signals accompanying each action , and studied with the greatest diligence and care the direction indicator and inclinometer . `` I have been noticing the indicator for the last hour , '' said Ralph , `` and it did n't change once . Are we going due north ? ''