midnight
`` We must make up our minds to be prisoners for some days to come ; and keep a constant watch , too , lest they should get upon our trail , and find their way up here . '' `` But how can you manage to keep watch alone ? You will require some sleep , '' I observed . `` Two or three hours are quite sufficient for me ; and they are not likely to attack us for the first hour or two before and after midnight , '' he answered . `` If they come at all during the night , it will be soon after dark , or just before dawn . I know their ways , and have thus been frequently enabled to get some necessary rest , even when I knew that they were on my trail . '' `` But you would surely be better for more than two or three hours of sleep ; and if you will drag my bunk to the door , I will keep watch while you rest . ''