midnight
The little pointer then accurately pointed to northwest , on the lower board , and by this means the changing of the upper board , so as to keep it due east and west at all times , will enable us to keep on our course . '' It was a long and weary night . One of them slept while the others were on duty . The boys knew the time on shipboard , where the day begins at midnight , and is divided into watches of four hours each , thus making three watches for the night and three for the day . A bell is struck every half hour , so that each watch is noted by the eight strokes of the bell . What is called the dog-watches occur between 4 and 8 P.M. , this period being divided in the first dog-watch between 4 and 6 , and the second dog-watch between 6 and 8 . `` Why should such peculiar times be taken , or the periods be divided up in that way ? ''