ten o'clock at night
From the sea , obviously . There must be , on the side of the offing , some fissure where boats could land at certain hours of the tide . But on the side of the land ? Beautrelet lay until ten o'clock at night hanging over the precipice , with his eyes riveted on the shadowy mass formed by the pyramid , thinking and pondering with all the concentrated effort of his mind . Then he went down to Etretat , selected the cheapest hotel , dined , went up to his room and unfolded the document . It was the merest child 's play to him now to establish its exact meaning . He at once saw that the three vowels of the word Etretat occurred in the first line , in their proper order and at the necessary intervals .