When he was gone, the barber turned to the young Arab. "Your father's son must always be welcome," he said, "but what of prudence? Is it not a necessary virtue? The Turk is stupid, Allah knows: witness the ass-head I have just anointed; but a watch is set upon all the approaches to the city, and you may tempt fortune too far. The house of Ionides was but lately occupied by a picket----" The young Arab started. "How did you know?" he asked. "Peace, peace!" replied the barber, with a significant gesture. "The walls have ears; the dust carries tidings. Is it not my business to know?" It was barely two hours since Burnet, slipping through the garden of a deserted house on the bank of the Tigris south of the city, found refuge in the building itself and watched for an opportunity, when, as he thought, no observer was near, to make an unobtrusive entrance into the streets. He knew of old how perfect was the barber's knowledge of what went on in Bagdad, and indeed throughout Mesopotamia; but this new illustration, this proof that his temporary shelter in the deserted house of the Greek merchant Ionides was already known to Firouz Ali, came upon him with something of a shock. Roger Burnet, as some may remember, was the son of a Cambridge scholar who had devoted the latter years of his life to archæological research in Mesopotamia. There Roger had spent the greater part of his boyhood, learning to speak Arabic almost as well as a native. Just before the outbreak of war he had been recalled from school in England by a peremptory telegram from his father, whom he found very ill. Mr. Burnet lingered for more than eighteen months in the hill village of an Arab chief, and it was not until June 1916 that Roger, after his father's death, was able to set off with the intention of joining the British army. Disguised as an Arab, he had travelled to Bagdad with a party of the chief's men, and taken counsel with Firouz Ali, an old friend of his father, a man of quick wit, and an important member of an organisation that was working for the release of the Arabs from the Turkish yoke.