The two advancing forces met at Mons, or, to be more accurate, the British force took up a defensive position at Mons--in conformity with the pre-arranged plan of extending the French line westwards--and there waited. From this time on, the doings of the Expeditionary Force become historically interesting, and its movements are worthy of study in detail. In the first instance, however, in order to arrive at a proper understanding of the circumstances which governed the position of the British troops on the occasion of their first stand, and which afterwards dictated the line of retreat and the roads to be followed in that retreat, and the successive points at which the retreating army faced about and fought, it is desirable to get a general grasp of the geographical side of things. The Germans were advancing from the north-east on Paris; that was their avowed intention; there was no secret about it; the leaders openly proclaimed their intentions; the soldiers advertised the fact in chalk legends scribbled on the doors of the houses; and--as the fashion is with Germans in arms--they were taking the most direct route to their objective, their artillery and transport following the great main roads that shoot out north-eastward from Paris towards Brussels, with their infantry swarming in endless thousands along the smaller collateral roads. Here and there, at intervals of from twenty to thirty miles, this system of parallel roads running north-east from Paris is crossed by other main roads running at right angles and forming, as it were, a skeleton check with the point of the diamond to the north. These main cross-roads had, in anticipation, been selected for the lines of defence along which our troops should turn and fight if necessary, for though it is laid down in the text-books of the wise that a line of defence must not run along a main road, such a road has obvious value for purposes of correct alignment. As the German advance was from the north-east, it is self-evident that the line of resistance or defence had to extend from north-west to south-east.