This reverse did not tend to expedite the campaign, and when it was finally launched on 31 July the weather interposed a third and fatal impediment. The first attack was successful enough. The French under Anthoine took Het Saas, Steenstrat, and Bixschoote; on their right Gough's Fifth seized Pilckem, St. Julien, Frezenberg, Verlorenhoek, Westhoek, and Hooge, the banks of the Steenbeck and the woods on the Menin road; and below that blood-stained highway Plumer's Second took Klein Zillebeke, Hollebeke, and Basse Ville on the Lys. It was, however, Von Arnim's plan to hold his front lines lightly and rely upon counter-attacks, and before the end of the day we had lost St. Julien, the north-east bank of the Steenbeck, and Westhoek. The key of the German position on the Menin road also remained in Von Arnim's hands, and no means had been found of dealing with his new and effective "pill-boxes." These were concrete huts with walls three feet thick, so sunk in the ground that their existence, or at least their importance, had escaped observation. They were too solid for Tanks to charge or for field guns to batter, and too small for accurate shelling by heavy artillery. Yet, crammed with machine guns and skilfully écheloned in the fighting zone, they presented a fatal bar to the rapid advance on which the success of our plan of campaign depended. Even so, it was not Von Arnim's skill and resource that finally ruined our prospects. Before night fell on the 31st the rain descended in torrents. For four days it continued, and even when it ceased it was followed by darkness worthier of November than of August. The field of battle was turned into a maze of lakes and bogs with endless shell-holes filled and hidden by the muddy water. The bombardment had broken the banks and dammed the streams, and rivers, instead of flowing, overflowed. Tanks became useless, and for men and animals there was as much risk of being drowned as shot.