Here General von Kluck's generalship was successful. It might have been regarded as risky to leave 100,000 men to guard a river confronted by 250,000 picked and reenforced French troops. But General von Kluck's faith in German guns and German gunnery was not ill-founded. This was the first of the open-air siege conflicts, and the French army had no guns which could be used against the German heavy artillery. Hence it followed that the brilliant work of the Sixth French Army on this first day of the battles of the Marne achieved no important result, for the long-range hidden howitzers, manned by expert German gunners and well supplied with ammunition, defied all attempts at crossing the little stream of the Ourcq. This first day's fighting on the Marne revealed one of France's chiefest needs--heavy artillery. The French light quick-firing gun was a deadly weapon, but France had neglected the one department of artillery in which the Germans had been most successful--the use of powerful motor traction to move big guns without slackening the march of an army. General von Kluck's artillery was impregnable to the French. Indeed, the Germans could not be dislodged from the Ourcq until the British Expeditionary Force sent up some heavy field batteries. It was then too late for the withdrawal from the Ourcq to be of any serious consequence in determining the result along the battle front. The afternoon of that day, when the Zouaves were driving the Germans across the Ourcq with the bayonet and were themselves effectually stopped by the German wall of artillery fire, General Joffre and Sir John French met. At last the British commander received the welcome news from the generalissimo that retreat was over and advance was about to be begun. "I met the French commander in chief at his request," runs the official dispatch, "and he informed me of his intention to take the offensive forthwith by wheeling up the left flank of the Sixth Army, pivoting on the Marne, and directing it to move on the Ourcq; cross and attack the flank of the First German Army, which was then moving in a southeasterly direction east of that river. "He requested me to effect a change of front to my right--my left resting on the Marne and my right on the Fifth Army--to fill the gap between that army and the Sixth. I was then to advance against the enemy on my front and join in the general offensive movement. German troops, which were observed moving southeast up the left bank of the Ourcq on the Fourth, were now reported to be halted and facing that river. Heads of the enemy's columns were seen crossing at Changis, La Ferte, Nogent, Chateau-Thierry, and Mezy. "Considerable German columns of all arms were seen to be converging on Montmirail, while before sunset large bivouacs of the enemy were located in the neighborhood of Coulommiers, south of Rebais, La Ferte-Gaucher, and Dagny.