It was because considerations such as these lay at the back of it, that the Germans, quite contrary to their traditions and training, went to the almost incredible labour of constructing across France from the Aisne ridge to Lorraine, that phenomenal line of more than 150 miles of deliberate fortifications and entrenchments. The risk involved in the Marne operations had, we now know, not been unforeseen. Nor were the consequences of failure, if it proved a grave failure, miscalculated. Indeed, the very precautions taken to prepare this line from the Aisne to Lorraine prove that they were not. That line, and that line alone, offered the probability of restoring the lost advantages, and of parrying the effects of the disaster. Enabling the Germans to hold their front and to bar the advance of the Allies with the minimum of force, that line at the same time was to have aided them--and this was its chief design--to throw the largest possible masses westward from their flank, pivoting on Noyon. By that movement they might cut the main Allied armies off from Paris. The scheme had the merit at once of boldness and of simplicity. For success it depended on bringing their fresh masses forward with the utmost rapidity. To that end the German military machine was worked to its fullest capacity. Thus began the new and enormous movement of Landwehr army corps into France. In part the German scheme was frustrated by the attack carried out by the British army in the Battle of the Aisne, and in part by the delays due to the very magnitude of the preparations. Unless attempted on a great scale a scheme of this character had better not be attempted at all. Since the success or failure of Germany in the war plainly hung upon it, the effort _had_ to be on a great scale. Of Germany's corps of Landwehr, by far the greater number were embodied during these weeks of September. It may seem to the uninitiated a simple matter to call up, embody, and make ready for the field a million and a half of men, or thereabouts. But even with a military mechanism like that of the German Empire, it is a complicated business. That all this was done in fact in rather less than three weeks is nothing short of marvellous. Because it was done, however, was the reason of the crisis at the beginning of October.