"Hullo," he yelled, then held his breath in tense silence to hear the response which came immediately. "Are you all safe?" he roared, his voice carrying easily through the open coal. "Ay," came the faint answer; "but the moss is rising in the heading and you'll have to hurry up." Robert knew this, and one of his helpers had gone down an old heading to explore and had returned to say that it was rising steadily and was now within two hundred feet from the old shaft down which he had descended. "Where away did the roof break?" roared Robert as he changed his second drill. "Half way doon the cousie brae," came the answer, "an' we're all shut in like rats. Hurry up and get us oot," and again the rickety, rackety noise of the boring machine began and drowned all other noises. He soon drilled his holes and he could hear them on the other side singing now some ribald song to keep up their courage, while others who were religiously inclined chanted hymns and psalms, but all were wondering whether Robert and his men would be able to break through the barrier in time to save them before the persistently rising moss claimed them. He charged his shots and called them to go back, telling them the number of his charges, then lit his fuse and ran out of the old level to wait in a place of safety while the explosion took place. Soon they boomed out and the concussion put them all in darkness; but they soon had the lamps re-lit and were back in among the thick volumes of powder smoke, groping about and shading their lamps and peering in to see what their shots had done to lessen the barrier between them and their imprisoned comrades. Then the shovels set to work and tossed the coal which the shots had dislodged back into the roadway and soon the boring machines were busy again, eating into the coal; for those tireless arms of Robert's never halted. He swung the handle or wielded the pick or shovel, never taking a, rest, while the sweat streamed from his body working like some mechanical product for always in his mind he was calculating his chances for being able to blast it through the barrier before the moss rose. "It has only a stoop length an' a half to rise now," reported one of the men. "It's creeping up like the doom o' the day o' judgment. But I think we'll manage. If these shots do as well as the last ones we should be within two feet of them, an' surely to God we can bite the rest of it, if we canna blaw it. Let me stem the shots, Rob, an' you take a rest."