The Germans showed more than common ingenuity in devising traps to hinder the advance of the Allies. In many instances a large number of shells would be placed in pockets under the roads so arranged that the weight of a passing wagon or motor lorry would explode them. They also arranged barbed-wire entanglements so that attacking troops would explode mines, but the Allies had learned through bitter experience the gentle ways of the enemy, and took effective means to render the German traps ineffective. Poisoned food and poisoned water marked the enemy's backward trail, but the Allies had long before concerted measures to protect the troops from such Teutonic pleasantries. The Allies continued to fight their way forward during the night of August 10, 1918, and on the following day the armies of Von Hutier and Von der Marwitz were in full retreat in the direction of Péronne, Nesle, and Ham. Important rear guards were sacrificed by the Germans to secure the safety of their main armies, and it became increasingly evident that they were running out of reserves. The Allied line on the front from Albert south to the Oise was carried forward, especially to the south, where the French were operating by themselves. During the night Haig's troops advanced their line on the high ground between Etinehem and Dernancourt. Farther south on the other side of the Somme the Germans, having received reenforcements, delivered powerful attacks against the British positions at Lihons and succeeded in making a temporary breach in the British line. In a fierce counterattack the British drove them back with heavy losses and the line was completely restored. The capture of the Massif of Lassigny by the French on August 12, 1918, was of first importance to the Allies, for the heights command a broad sweep of difficult country and when in German hands were a formidable obstacle to the Allied advance. German positions at Roye were now threatened on three sides--north, west, and south--as the Allies pushed their lines forward. The British gained ground to the east of Fouquescourt, while the French captured the village of Armancourt, and Tilleloy and the Bois des Loges. The heavy guns of the Allies continued to shell the Somme bridges in the Chaulnes region which the Germans would have to cross if they were forced to evacuate this territory. South of the Somme Haig's troops captured the village of Proyart and linked up their positions east of Mericourt with those to the east of Etinehem, which is on the northern bank. While the Allies' advance had slowed down owing to the increasing number of reserves which the Germans threw into the battle line the enemy was gradually being thrust out of the strongest positions which he had held so long. Since the beginning of the Allied counteroffensive which began on July 18, 1918, they had captured over 70,000 prisoners, about 1,000 guns and over 10,000 machine guns.