schist。
Hollow； cavernous noises resounded on all sides。 Draughts of air rushed along the ventilating galleries； and the wooden swing…doors slammed beneath their violent gusts。 In the lower tunnels； trains of trucks kept passing along at the rate of fifteen miles an hour； while at their approach electric bells warned the workmen to cower down in the refuge places。 Lifts went incessantly up and down； worked by powerful engines on the surface of the soil。 Coal Town was throughout brilliantly lighted by the electric lamps at full power。
Mining operations were being carried on with the greatest activity； coal was being piled incessantly into the trucks； which went in hundreds to empty themselves into the corves at the bottom of the shaft。 While parties of miners who
had labored during the night were taking needful rest； the others worked without wasting an hour。
Old Simon Ford and Madge； having finished their dinner； were resting at the door of their cottage。 Simon smoked a good pipe of tobacco； and from time to time the old couple spoke of Nell； of their boy； of Mr。 Starr； and wondered how they liked their trip to the surface of the earth。 Where would they be now？ What would they be doing？ How could they stay so long away from the mine without feeling homesick？
Just then a terrific roaring noise was heard。 It was like the sound of a mighty cataract rushing down into the mine。 The old people rose hastily。 They perceived at once that the wa