About fifteen miles to the south of Piatek is Lodz, the "Manchester of Poland." It contains half a million people, and has grown more rapidly than any other city of Europe. Its chief industry is cotton, but there are also large factories in which silk, woollen, and linen fabrics are made, as well as numerous dye-works, flour mills, distilleries, and machine shops. The Germans had captured it during their first march on Warsaw, but had lost it during the retreat. They were now to make a bold bid for it again. Accordingly the German right now pressed hard against the Bzura at B, south of the marshes. While the right was crossing the river at B, the extreme left moved towards Plock, so as to outflank the Russian position by crossing the river at A. The main attack, however, was to be made not on the flanks but in the centre, across the causeway at C. Now I want you to notice that if Russian reinforcements could have come up from the south, the German flanking forces at B would have been hemmed in between the Russians to the north of Lodz and those advancing on the city from the south. Von Hindenburg, however, felt quite sure that the Russians from the south could not arrive in time owing to the broken roads and railways. Long before they came up he hoped to be in Warsaw. [Illustration: A German Battery overwhelmed by Cossacks. This grim picture illustrates the fate of the Germans who were trapped in the "pocket" as described on page 255.] An extraordinary state of things soon occurred. At first the Russians beat off attacks on the causeway, and held the German army in the villages north of the marshes. But on 19th November von Mackensen made a huge effort. He crossed the causeway, and pushed the Russians well south of Piatek. For the next four days his troops tramped across the causeway, and the Russians fell back more and more, till there was a deep sag in their line east of Lodz. Von Mackensen pushed this sag deeper and deeper, and wider and wider, until it resembled a pocket, and on 23rd November the bottom of the pocket fell out, and the Russian army was split into two parts, as shown in the diagram on the next page. The Germans burst through the gap, and the Russians were now in a most dangerous plight, especially as the enemy was bringing up strong forces both from the south-east and the south. Lodz was now being attacked from the front, from the flank, and from the rear. The Germans appeared to have succeeded beyond their wildest dreams.