ten
o'clock at night
I did not even know whether it was night or day by the watch , nor would it have mattered had I not known the one from the other , as the brightest sun could not have lent a ray of his light to cheer my dungeon . It chanced , however , that I _ did _ know the night from the day . No doubt you will wonder how I came by this knowledge -- since I had kept no time for the first hundred hours after getting aboard , and there was then , in the complete darkness that surrounded me , no means of distinguishing the one from the other . I had a means of telling , however , and it was this : During all my life I had been trained to the habit of going to bed at a particular hour -- ten o'clock at night -- and also of rising at six exactly . This was a rule in my father 's house , as well as that of my uncle -- in the latter , indeed , I was compelled to observe it with a stern exactitude . The consequence of this habit was , that whenever the hour of ten drew nigh , I naturally felt the inclination for sleep ; and the habit had grown so fixed , that , notwithstanding the change of circumstances , it still continued . This I was not slow to observe .