noon
This diary is usually called the ship 's log . And every day he writes in it what happened that day ; the courses the ship sailed and the number of miles she sailed on each course ; the sails that were set and the direction and strength of the wind ; and the state of the weather and the exact part of the ocean she was in and the time that she was there . The exact part of the ocean that the ship is in is usually found by looking at the sun , just at noon , through a little three-cornered thing , called a sextant , that is small enough for the captain or the mate to hold in his hands ; and by seeing what time it is , by a sort of clock , when the sun is the very highest . Then the captain goes down into the cabin and does some arithmetic out of a book , using the things that his sextant had told him , and he finds just exactly where the ship was at noon of that day . Then he pricks the position of the ship on a chart , which is a map of the ocean , so that he can see how well she is going on her course . Sometimes it is cloudy at noon , so that he ca n't look at the sun then , but it clears up after dark . Then the captain looks through his sextant at the moon , or at some bright star , and finds his position that way .