When Turkey entered the war against the Allied Powers, her officers had every reason to expect that the British or French fleets would attempt to force the Channel. The military prize, Constantinople and the control of the Black Sea (whether for peace or for offence), was too great a temptation to be resisted. Helped by their German allies they prepared for this attack with skill, knowledge and imagination. The Turks had no effective battle fleet, as in the sixteenth century, when they sought their enemies upon their own coasts; and had they had one they could not have passed the British fleet blockading the Dardanelles; but they prepared the channel and its shores so that no enemy ship might pass to seek them. More than the two great wars, in South Africa and Manchuria, the present war has shown: (a) that in modern war, defence is easier and less costly in men and munitions, however much less decisive, than attack; (b) that the ancient type of permanent fortress, built of steel, concrete and heavy masonry is much less easy to defend against the fire of heavy modern howitzers and high explosives than temporary field works, dug into the earth and protected by earth and sandbags; (c) that the fire of modern long range guns is wasteful and ineffective unless the object fired at can be accurately ranged, and the fire controlled by officers who can watch the bursting of the shells on or near the target; (d) that in restricted waters the fixed or floating mine, filled with high explosive, is a sure defence against enemy ships. Beginning with proposition (a), the Turks argued that (unlike most defences) a defence of the passage of the Dardanelles against naval attack might well be decisive (i.e., that it might well cause the attack to be abandoned or even destroy the attacking ships) since ships engaged in the attack would be under every disadvantage, since: (b) Their guns, however heavy, would not be overwhelmingly successful against temporary field works and gun emplacements. (c) Their officers, unable in the first place to locate the guns hidden on the shore, would be unable to observe the effect of their fire, and therefore unable to direct it, and this disadvantage would become greater as the ships advanced within the channel and became shut in by the banks. (d) They would be unable to enter the channel until the waters had been dragged for mines by mine sweepers. The batteries of field guns hidden on the coast would perhaps be sufficient to stop the progress of the mine sweepers. If not, floating mines, alongshore torpedo tubes, and the accurately ranged and directed fire of heavy howitzers would perhaps sink the ships of war as they advanced.