Left to itself, the garrison could do next to nothing. It could account, and did account, for a large number of the enemy in front of its earthen ramparts. But sooner or later its doom was certain. Its fall was only a question of days, or even of hours. Like all fixed forts, ancient or modern, exposed to the fire of modern siege artillery, it was, in itself, about as impregnable as an umbrella. It lay on the extreme left of the French fine from the Meuse to Pont-à-Mousson. To the north it was protected to a certain extent by St. Mihiel, supposing that St. Mihiel contained any troops. But its real defences, on which the French had spent a considerable sum of money before the war, consisted of a large number of trenches, strengthened with concrete, some miles in advance of it on the farther side of the Hauts de Meuse, between Les Eparges and Thiaucourt. They occupied, that is to say, practically the whole of the space which I have spoken of as the gap in the lines of the armies, and which was partly accounted for by the fact that as the German Fifth Army inclined slightly westwards, to keep in touch with the others which had Paris as their principal objective, the French Third Army was to a certain extent obliged to follow it, besides which for the time being the French Second and the German Sixth Army were too much occupied with their own affairs round Nancy to be able to extend very far in the direction of Verdun. But the carefully prepared trenches were there all the time, and, as far as it is possible to judge without knowing all the circumstances, might and should have been held almost indefinitely, instead of which the chief purpose they seem to have served was to act as a shelter for the advancing Germans. By some further mischance or miscalculation, at this particularly critical moment, two or three days after the Germans had begun the general bombardment of the river forts, St. Mihiel was suddenly left almost wholly denuded of troops, with the result that on August 24th the enemy’s advance-guard walked into it practically unopposed. There are two or three possible explanations of the way in which this regrettable mistake was brought about, in all of which there is probably a certain amount of truth. The French may have made up their minds that the enemy had for the moment given up the idea of making a determined effort to cross the river. Or they may have still clung to the mistaken belief that the fort on the height, chosen centuries ago by the Romans as the most commanding strategic position of the district, was strong enough to defend itself and look after the river as well. Or, thirdly, they may have concluded that they had no choice in the matter, and that the pressure nearer Metz, on the right flank of their line forming the south side of the St. Mihiel triangle, was for the moment more dangerous than that on their left, and that it was safe to move part of their force on the Meuse across to the Moselle.