Through the lens of his helmet the Sub saw nothing of the nature of a flash. He heard the roar; it smote upon his temples like the blow of a club, as a rush of violently agitated water all but swept him from his precarious position. His head-dress came in contact with a hard substance. It seemed as if the metal helmet was collapsing under the shock. Still he held on, wondering dully why he had not been pulverized by the explosion, or at least his diving-dress torn asunder. Nothing of this nature happening, he sought his companions. Cassidy was still there, literally hugging the outboard part of the propeller shafting, but of Payne there was no sign. All the tools had vanished, with the exception of one hack-saw. The rest were lying on the bottom of the sea, ninety feet or more below, doubtless with the unfortunate Payne. The Sub still retained his electric lamp. Cassidy also had his, but the light had failed. The hull of the submarine was still oscillating gently under the influence of the disturbed water. It was a good sign. Had the plating been shattered by the explosion, the vessel would have sunk like a stone. As it was, she still retained a reserve of buoyancy, but was prevented from rising only by the retaining influence of portions of the steel net. Subsequent events proved that this was a blessing in disguise, for R19 would have risen to the surface in the full glare of the German torpedo-boat's search-lights. Signing to Cassidy, the Sub indicated that the task of freeing the propeller should proceed. It was a slow job with only one hack-saw at their disposal, but one by one the tough strands were severed. Fordyce was on the point of giving his companion a spell, when a scratching, rasping noise against his helmet rudely attracted his attention. He was just in time to avoid a kick on the plate-glass front of his head-dress from a leaden-soled boot, as Payne, making his way down the tapering stern of the submarine, was gamely returning to his interrupted task. The explosion, the effect of which was greatly mitigated by the buffer of water, had wrenched him from his perch, and had lifted him 20 or 30 feet vertically upwards, depositing him upon the rounded afterpart of the submarine. The churning sounds of the Hun torpedo-boat's propellers had now ceased. It was indeed fortunate, Fordyce decided, that the vessel made no further attempt to use explosive charges. The Sub had no idea of what time had elapsed since he and his companions left the submarine. It was certainly not far short of an hour. To let the rest of the crew know that they were still alive and, what was almost as important, active, they hammered upon the steel plating.