Facing the British were three German armies. The Seventh, under General Otto von Below, on the right held the front from north of the Scarpe to the Scheldt at Cambrai where General von der Marwitz with the Second Army prolonged the line down to north of St. Quentin. General von Hutier, commanding the Eighth Army, held the line on Marwitz's left between Omignon River and the Oise, where an army under General Böhm faced the Third French Army under General Humbert. The German offensive had been prepared with the greatest care; every division had rehearsed the part it was to play when the hour of attack should come. Before the push the British lines were deluged with shells, and this was followed by showers of projectiles that liberated poisonous gases. The infantry now went forward in waves following each other closely. The first wave of troops would be swept almost away by the British gun and rifle fire, but those that remained alive hung on until joined by more waves of men, when using flame projectors they proceeded to drive the British out of the trenches. The Germans were prodigal in the waste of man power, counting on weight of numbers to crush their opponents. After they had captured the first British line, the rear lines were deluged with fire from the machine guns, rifles, and every form of small artillery. This overpowering avalanche of death-dealing projectiles prevented the British in the rear from coming to the rescue of their fellow soldiers in the first line. Under the protection of this storm of bullets the Germans advancing in waves penetrated the British second line. After they had gone some distance the first ranks of infantry lay down, and permitted other waves of men to pass through their ranks. Great numbers of three-inch guns and small cannon on low carriages that could be swiftly moved were now brought up behind the infantry and the attack went on. The German attack was directed against the center of the Allies' position. Their aim was to drive a great salient on a front of fifty or sixty miles through the occupied lines which would divide the French and British, after which they were to be dealt with separately. The German objective was Amiens, which, situated astride the Somme, is on the main trunk-line railroad from Paris to the Channel ports of Boulogne and Calais, the most important strategical point in northern France. If the Germans succeeded in gaining their objective, Sir Douglas Haig's troops separated from their French allies would be penned up in a northwestern corner of France with their backs to the sea, or they would be forced to retreat behind the lower Somme in order to cover their communications with Havre.