laurence disliked that he was not sure of his power to do so , and disliked still more discussing the subject with hammond ; he excused himself and stepped outside , to join granby in his usual haunt of late : sitting in what might have been a casual manner upon the roof of the hall , which offered him an excellent vantage point over the city : as dragons came and went , he sketched them and made note of their points in a crabbed and awkward hand which contrasted peculiarly with the precision and clean lines of his sketchwork .