As these thoughts passed through French’s mind a further consideration struck him, a consideration which he saw might not only prove a fifth test of the case he was trying to make, but which, if so, would undoubtedly be the most conclusive of them all. He turned once more to Daw. “There’s a point which is worrying me rather, Sergeant,” he declared. “Suppose one of these two men murdered the other on that night. Now why would the murderer go to the trouble of getting the body into the works and sending it off in the crate? Could he not simply have thrown it into one of these mires?” Daw nodded. “I thought of that when you suggested your idea, but I don’t believe there’s anything in it. It wouldn’t be so easy as it sounds. In fact, I couldn’t see any way it could be done.” “I’m glad to hear you say so, Sergeant. Explain, please.” “Well, if you go into one of those places and begin to sink you throw yourself on your back. As long as your weight is on the small area of your feet you go down, but if you increase your area by lying on your back you reduce the weight per unit of area and you float—because it really is a kind of floating. You follow me, sir?” “Quite. Go ahead.” “Now if you walk to a soft place carrying a body you have doubled the weight on your feet. You will go down quickly. But the body won’t go down. A man who tried to get rid of his victim that way would fail, and lose his own life into the bargain.” “That sounds conclusive. But I didn’t know you could save yourself by throwing yourself down. If that is so wouldn’t Berlyn and Pyke have escaped that way? Why did you then accept the idea that they had been lost?” “There were two reasons. First there was nothing to make me doubt it, such as knowing about the crate, and secondly, though the accident was not exactly likely, it was possible. This is the way I figured it out. Suppose one of these mists had come on. They do come on unexpectedly. One of the men gets into a soft place. Mists are confusing, and in trying to get out, he mistakes his position and flounders in further. That’s all perfectly possible. Then he calls to the other one, and in going to the first one’s help the other gets in also—both too far to get out again.” “But you said it was a clear night?” “So it was when I got there. But three or four hours earlier it might have been thick.” “Now, Sergeant, there’s another thing. Could the murderer not have used some sort of apparatus, a ladder or plank to lay on the soft ground, over which he could have carried the body and escaped himself? Same as you do on ice.”