"That passage is closed, at any rate," decided Captain Nicholson, glancing in the direction of the mound of debris and the displaced girders. "M'Kane and I have explored the entrance, There's been a big fall. The supplementary shoots are also choked. We followed a level working for nearly a hundred yards. It leads nowhere. Fritz never had time to finish it. Look here, this torch won't hold out for ever. The battery's running down. How's Selwyn?"