about five o'clock
After the delay thus caused , the procession again started on its perilous route . Dick Sands continued to walk at the head , in order to test the stability of the footing ; Action followed , holding Cousin Benedict firmly by the arm ; Tom took charge of old Nan , who without his support would certainly have fallen into the quagmire ; and the three other negroes carried the litter in the rear . It was a matter of the greatest difficulty to find a path that was sufficiently firm ; the method they adopted was to pick their way as much as possible on the long rank grass that on the margin of the swamps was tolerably tough ; but in spite of the greatest precaution , there was not one of them who escaped occasionally sinking up to his knees in slush . At about five o'clock they were relieved by finding themselves on ground of a more clayey character ; it was still soft and porous below , but its surface was hard enough to give a secure foothold . There were watery pores that percolated the subsoil , and these gave evident witness to the proximity of a river-district . The heat would have been intolerably oppressive if it had not been tempered by some heavy storm-clouds which obstructed the direct influence of the sun 's rays . Lightning was observed to be playing faintly about the sky , and there was now and again the low growl of distant thunder .