Here, then, you have a quadrilateral of railways about fifty miles in length. Within that quadrilateral is extremely bad country--lakes, marshes, and swamps--and the only good roads within it are those marked in single lines upon my sketch--the road from Allenstein through Hohenstein to Niedenberg, and the road from Niedenberg to Passenheim. As one goes eastwards on that road from Niedenberg to Passenheim, in the triangle Niedenberg-Passenheim-Ortelsberg, the country gets worse and worse, and is a perfect labyrinth of marsh, wood, and swamp. The development of the action in such a ground was as follows:-- The Russian commander, Samsonoff, with his army running from Allenstein southwards, was facing towards the west. He had with him perhaps 200,000 men, perhaps a trifle less. His reconnaissance was faulty, partly because the aeroplanes could discover little in that wooded country, partly because the Staff work was imperfect, and his Intelligence Department not well informed by his cavalry patrols. He thought he had against him to the west only weak forces. As a fact, the Germans were sending against him what they themselves admit to be 150,000 men, and what were quite possibly nearer 200,000, for they had drawn largely upon the troops within Germany. They had brought round by sea many of the troops shut up in Königsberg, and they had brought up the garrisons upon the Vistula. Further, they possessed, drawn from these garrisons, a great superiority in that arm which throughout all the earlier part of the great war was the German stand-by--heavy artillery, and big howitzers capable of use in the field. On Wednesday, 26th August, Samsonoff first discovered that he had a formidable force in front of him. It was under the command of von Hindenburg, a man who had studied this district very thoroughly, and who, apart from his advantage in heavy artillery, knew that difficult country infinitely better than his opponents. During the Wednesday, the 26th, Hindenburg stood upon the defensive, Samsonoff attacking him upon the line Allenstein-Soldau. At the end of that defensive, the attack on which was badly hampered in so difficult a country, von Hindenburg massed men upon his right near Soldau. This move had two objects: first, by pushing the Russians back there to make them lose the only good road and railway by which they could retire south upon their communications into the country whence they had come; secondly, to make them think, in their natural anxiety for those communications, that his main effort would be delivered there to the south. As a fact, it was his intention to act elsewhere. But the effect of his pressure along the arrow _a_ was to give the Russian line by the evening of that Wednesday, the 26th of August, the form of the line 1 upon Sketch 73.