Meanwhile, between the fields of the two French adventures into German Lorraine and Belgian Luxembourg, the enemy had been allowed without serious resistance to occupy the Briey region, and so to carry over from France to Germany an iron- and coal-field of the utmost value. “Briey has saved our life,” the ironmasters of the Rhineland declared later on, with some exaggeration. Had it been modernised, the small fortress of Longwy, situated above the River Chiers three miles from the Luxembourg frontier, might have been an important element in a defence of this region. In fact, its works were out of date, and were held at the mobilisation by only two battalions of infantry and a battery and a half of light guns. The Germans summoned Colonel Darche and his handful of men to surrender on August 10; but the place was not invested till the 20th, the day on which the 3rd Army was ordered to advance toward Virton and Arlon, and to disengage Longwy. Next day, Ruffey was north and east of the place, apparently without suspecting that he had the Crown Prince’s force besieging it at his mercy. On the 22nd, it was too late; the 3rd and 4th Armies were in retreat; Longwy was left to its fate.[19] V. THE BATTLE OF CHARLEROI–MONS The completest surprise naturally fell on the west wing of the Allies; and, had not the small British force been of the hardiest stuff, an irreparable disaster might have occurred. Here, with the heaviest preponderance of the enemy, there had been least preparation for any hostilities before the crisis was reached. On or about August 10, we war correspondents received an official map of the “Present Zone of the Armies,” which was shown to end, on the north, at Orchies——16 miles S.E. of Lille, and 56 miles inland from Dunkirk. The western half of the northern frontier was practically uncovered. Lille had ceased to be a fortress in 1913, though continuing to be a garrison town; from Maubeuge to the sea, there was no artificial obstacle, and no considerable body of troops.[20] The position to be taken by the British Expeditionary Force——on the French left near Maubeuge——was only decided, at a Franco-British Conference in London, on August 10.[21] On August 12, the British Press Bureau announced it as “evident” that “the mass of German troops lie between Liège and Luxembourg.” Three days later, a Saxon advance guard tried, without success, to force the Meuse at Dinant. Thus warned, the French command began to make the new disposition of its forces which has been alluded to.