"It's a general move, eh?" Philip asked his chum, meeting him as he crossed from his bivouac of the night before to fall in with his regiment. "Please note that I am appealing to you, Geoff, as a man who ought to know everything that's happening; if not, what's the good of a fellow being on the Head-quarters Staff. What's up?" "I know as little as you do," came the laughing rejoinder; "but I can guess, and my guess is that we are on the way up the river to take Kurna. It's somewhere about there that the Rivers Tigris and Euphrates come together, and I suppose it's a point of some strategical importance." "Strategical! Ahem!" coughed Philip. "Ain't we going it! From talking Turkish we're now getting to use quite military sort of language!" It was just one of his little pleasantries, and, indeed, Geoff was the sort of young fellow who never resented being twitted, and, moreover, he was rather given to being facetious himself, especially when with Philip. However, he was too busy on this eventful morning to spend time in bantering, for indeed much was about to happen. We have mentioned already that the head of the Persian Gulf is of no little importance to Great Britain, and that for many reasons, one of which, no doubt of somewhat recent origin, has to do with the supply of oil for our battleships--a supply which is piped from the oil-fields in Persia, under the control of Britain. The pipe-line itself passes down in the neighbourhood of Ahwaz, towards which place a portion of the Expeditionary Force was at that moment proceeding, with a view to seizing it and holding it against the enemy. But the safe possession and protection of that oil-line was not the only reason for sending an Expeditionary Force to Mesopotamia. There were other, and perhaps somewhat complex reasons, which can only be broadly dealt with in this cover. International questions are involved, the discussion of which would take up an abundance of space, and might well prove not altogether interesting. But it becomes necessary at this stage to give some idea, even if it be only a meagre description, of other reasons which induced the British Government to dispatch a force to the valley of the Euphrates.