The Persian Gulf and the coast which borders it may be said to be the eastern end of the Turkish possessions, while Turkey in Asia is bounded to the north and east by the difficult country of Persia. Already we have sketched in the position of Russia and of the Caucasus frontier, and have stated that the coming of Turkey into this gigantic conflict on the side of Germany and Austria--the Central Powers--had a distinct and direct effect on the fighting in Europe, seeing that the Turks were able to dispose of some excellent troops, and were able to dispatch them promptly to the Caucasus area, where, fearing the invasion of southern Russia, the Tsar was forced to march and post an adequate army--an army which, but for the Turks, might have been merely a frontier guard, allowing of the bulk of the troops being dispatched to Poland, there to meet Germany and Austria. Thus the entry of Turkey into the war affected Great Britain and her allies, but yet cannot be said to have called for an expedition on our part to the eastern end of the Turkish Empire. Distances are huge in the country governed in name by the Sultan of Turkey, and in actual fact by the Young Turk party, who, let us explain, are themselves swayed, if not actually governed, by the emissaries of the Kaiser in Constantinople. From Constantinople itself to Bagdad, or to the Caucasus front, is roughly a thousand miles, and from Bagdad to the head of the Gulf of Persia is perhaps some five or six hundred more. But, as we have shown, a blow dealt at a distance may, in the war which is now raging, affect the course of that war at some far-off point--as the amassing of Turkish troops on the Caucasian frontier had already undoubtedly affected the fortunes of the Russians in Poland. Thus our Expeditionary Force sent to the valley of the Euphrates and of the Tigris might very well, though that point is at such a great distance from the Russo-Turkish frontier, affect the fortunes of the Turkish troops fighting the Russians in the Caucasian Mountains; for undoubtedly the enemy would need to send troops against us. But, and this is a matter of considerable importance, the valley of the Euphrates is notoriously unhealthy and is an extremely difficult country to negotiate. Practically roadless, and without a railway, it is not a country easy of invasion, and at the best no rapid advance was to be expected. Thus the force which Britain could afford to send to this somewhat out-of-the-way part of the world, though it might affect the Turks to some degree, could not be expected to make a very serious difference to them. It would seem, therefore, that there was another reason, and a better one, for our sending troops to Mesopotamia.