Geoff was not such a young soldier that he could not at once perceive the importance of the information just conveyed to him. With the knowledge he already had of Mesopotamia, he had been able to inform his friend on the Staff that, above the town of Basra, wide stretches of marsh would be discovered, which at certain seasons of the year were greatly extended by the heavy rains which fell in that part of the world. But if residence in Mesopotamia had given him some idea of the course of the rivers, of the towns and villages dotted here and there, and of the numerous peoples who inhabited that region, he could not, naturally enough, be expected to know where the Turks had disposed their forces on the outbreak of this gigantic war. Some had undoubtedly been posted towards the mouth of the Shatt-el-Arab, for had not the Indian horse already had a lively brush with them? But where were the others? Higher up the river, preparing their defences and waiting for the onward march of the British forces, or sneaking in those marshes to the west of them, which spread themselves along the broken and irregular course of the River Euphrates, from a point perhaps fifty miles away to the spot where the river joined with the main channel of the Tigris? And if they were there, hidden in the swamps, perhaps camping on some piece of ground elevated sufficiently to give them a dry footing, then indeed they would be a menace to the safety of the forces invading the country. They might march down along the edge of the swampy ground, or if provided with native boats, known as bellums, might steal over the shallow waters and cut off the retreat of Geoff and his comrades.

"Chief," he said suddenly, "you know this marsh land, perhaps, and you would help us to discover these enemies?"

"My master, an Arab is a man of the desert, a man who is happiest when far away in the open, or when mounted upon his horse, with leagues of sandy soil before him. We are not given to venturing upon the water, and thus it follows that I am ignorant of these marshes, and could be of little service. But listen, my master! There is one within this town of Basra who could assist you. A man known to me—a native of these parts, of uncertain nationality. He is but a poor fisherman; and if His Highness, whom I have met, cares to arrest him, he has then but to command and the man will carry out his bidding."

"And suppose—for I must tell you, Chief, that we of Great Britain do not force our orders upon helpless and poor people—supposing a reward is offered to this man. What then?" asked Geoff.

"Then, indeed, you may count upon his assistance, his ready assistance," said the chief, "and for all I know he might be willing enough to carry out the work because of his hatred of the Turks. Yes, my master, they are hated in this part of the world. Though they molest the Arabs but little, and indeed fear us greatly, for we are swift to move from spot to spot, and can strike a blow and be gone in an instant, yet to those who live their lives on the bank of the river, where the Turks can reach them easily because of their boats, to these they are often harsh and cruel, taxing them heavily, and treating them as slaves, or little better."

Geoff gave himself a few moments in which to deliberate, and then, asking the chief to accompany him to Head-quarters, he sent in a message to the Intelligence Officer who has already been introduced to our readers. To him he promptly gave full information of the marshes, and of the rumoured Turkish forces lying hidden in them. It was apparent at once that this Staff Officer considered the news of the utmost importance; for, bidding Geoff stay outside the house taken over by the General, he disappeared inside, and remained there for quite a considerable period. When he came out again, it was clear from the expression on his face that he had come to some decision.

"Those Turks must be found, and routed," he told Geoff. "And of course we shall be glad to take advantage of the services of the native whom the chief has mentioned to you. That means that you must go along too, Keith, for otherwise there will be the language difficulty. Orders will be given to the naval contingent. There are some motor launches with them, and I imagine that one of them should be able to make its way through the marshes. In fact, the expedition will have to be a naval one almost entirely, with you and this native guide accompanying."

Geoff coughed discreetly to attract the Staff Officer's attention, for of a sudden a brilliant thought had struck him. He was thinking of his chum Philip, who had almost "lived in his pocket" these last few days, and who eagerly waited a summons to accompany our hero.

"You are the luckiest beggar I ever came across!" he had told Geoff when he had heartily congratulated him upon his capture of the Arab chief. "Any other fellow would have been shot down by those Turkish bullets, which Daglish says you were idiot enough to stand up and face—but I'll be honest, though, and add that Daglish, though he said at first you were an idiot, said afterwards that he admired your pluck, and wondered whether he'd have been as cool if he'd been in your place. But we're not talking about Daglish, we're talking about you and myself, and don't forget that I come into the discussion. What I want to impress upon you is the decided need you have of assistance. You can't go off on jaunts like that without having another fellow to look after you. Supposing one of those Turkish bullets had hit you after all, what then?"

He stood in front of Geoff and watched him expectantly.