six o'clock
Using his knife instead of a stone , he was able the next day to convert their knives into much better saws than his own had been ; and the other two rivets were cut in a much shorter time than the first . They waited another week and then the wind began to rise , and by evening half a gale was blowing , and the rain falling heavily . There was no moon , and the night would be admirably suited for their purpose . Their supper was brought in at six o'clock . Knowing that they would not be visited again until the morning , they at once began work . As soon as they had finished cutting one rivet they tried the bar , and their united strength was quite sufficient to bend it far enough to allow it being withdrawn from the rivet ; then , throwing their weight upon it , it turned upon the bolt at the other end , until it hung perpendicularly . In another half hour the other two bars were similarly removed , and the heavy shutters opened .