He lay very still till the motor disappeared from sight. Then he took a compass bearing to the point at which he had seen it. He stuck his stick in the ground and tied a handkerchief to it, to afford him a very necessary point from which to work, for by now he knew that it might cost him three miles of roundabout walking to make his way to the spot even though it was under a mile away in a straight line. Then he set off.

Again and again he had to retrace his steps, to find some way of crossing the many dykes, and he was duly thankful that he had had the intelligence to make an improvised flag which afforded him a definite clue to his starting point in the dreary sameness of the marsh. Something over an hour of tedious walking it took him to cover the distance. At last a hazardous journey over a slimy plank brought him to a narrow and almost imperceptible roadway. And there imprinted on the turf were the slight but unmistakeable tyre marks of a big motor car.

Labar whistled cheerfully as he bent to examine them.