"How the deuce do you keep it up, Colin?" the major asked him. "I'm an old hand at the job, and yet I've got a temper like devilled bones. You seem as chirpy as if you were going out to fish a chalk-stream on a June morning."

"Well, the fact is——" and Colin pulled himself up short, knowing that he could never explain. He felt miserably that he had an unfair advantage of the others. Poor Bellew, who groaned and swore in the heat at his side, knew nothing of the Rim of the Mist. It was really rough luck on the poor beggars, and who but himself was the fortunate man?

As the days passed a curious thing happened. He found fragments of the Other world straying into his common life. The barriers of the two domains were falling, and more than once he caught himself looking at a steel-blue sea when his eyes should have found a mustard-coloured desert. One day, on a reconnoitring expedition, they stopped for a little on a hillock above a jungle of scrub, and, being hot and tired, scanned listlessly the endless yellow distances.

"I suppose yon hill is about ten miles off," said Bellew with dry lips.

Colin looked vaguely. "I should say five."

"And what's that below it—the black patch? Stones or scrub?"

Colin was in a day-dream. "Why do you call it black? It's blue, quite blue."

"Rot," said the other. "It's grey-black."

"No, it's water with the sun shining on it. It's blue, but just at the edges it's very near sea-green."

Bellew rose excitedly. "Hullo, Col, you're seeing the mirage! And you the fittest of the lot of us! You've got the sun in your head, old man!"