At all other times, and indeed at all times, the rivers themselves were the chief means of communication for troops and supplies; and boats of any carrying power were few. Even when armed movement on land was possible, any advance against an enemy in position was a formidable task, for the flat ground afforded not a vestige of cover, and troops had often to go forward to the assault of trenches over ground as smooth and bare as a billiard-table, perhaps up to their knees in mud, with deep swamps on each side preventing any attempt at a turning movement. Mud, indeed, proved to be a more formidable obstacle than mountains and ravines. Troops could not advance over it with any freedom or swiftness, and they could not camp in it without misery and loss; nor could they be fed in large numbers, for it made the transport of supplies very difficult. Then the whole country, though not really friendly to the Turks, was inhabited by Arabs who were anything but friendly to an invader. Whether in the marshy lands near the rivers or on the dry plains beyond, they were always hanging on the flanks of an advancing or retreating force, their desert horsemen as elusive as the “web-footed” men of the marshes, swift to gather and as swift to vanish in the mirage of an enchanted land where all seemed fantastic and unreal. With stubborn Turkish soldiery, organised by Germans, intrenched in large numbers along the river lines, and supported by larger numbers of these irregular auxiliaries on every side, the country was no easy field of action for a British army. Nevertheless, in spite of all difficulties of climate and ground, the British expeditionary force had by the autumn of 1915 established itself in control of the river mouths, with a considerable Turkish province in its hands. Then, in an evil hour, came the decision to advance on Baghdad, and a single British Division was pushed forward. It was a very daring if not an insane project, and it failed. Before the end of the year the unfortunate Division found itself besieged by superior forces at Kut-el-Amara, and in the following April, after a siege of five months, a starving British force of more than 10,000 men, nearly 3000 of them white men, was marched away by the Turks into bitter captivity. This was the heaviest blow that had ever been dealt to British arms and British prestige in Asia. Not only had 10,000 men been taken prisoners, but the Turks had inflicted upon other British forces trying to relieve them a series of bloody repulses. Struggling forward, time after time, with splendid devotion over the muddy flats, in vain attempts to drive from strong lines of trenches an enemy superior in numbers, our soldiery, white and black, had lost over 20,000 men in killed and wounded, and had been forced to admit that for the time they could do no more. The Turks had won a striking success, the measure of which to Great Britain was the loss of an Army Corps.