Thus hour by hour our attack pressed home like waves of an incoming tide, and from a distance the effect was most curious to watch. Two long undulating lines—a light blue haze hanging over them—each seemed to be backed by some elastic force; as the equilibrium at one point was disturbed, one line recoiled and the other pressed forward till flanking fire brought it again to a stop for the moment. By noon the edge of the high ground overlooking the valley, through which runs the Rhine-Marne Canal, was reached, and now the flood was running strong in our favour. Then we could see, too, how these disturbances in the equilibrium of the two lines were occasioned. The smaller units of the French thought too much of their flanks, too little of their centre. Thus, where two battalions or companies touched, the men balled up and crowded together, offering a better target; then the fire from the centre relaxed, and the moment the pressure of the enemy’s fire gave way, the Germans dashed forward to fill up the vacuum. Soon, too, the French endeavoured to bring up their reserves in column, for their men would no longer advance in extended order; and now the small calibre rifle and its great penetration justified its existence; I had not thought much of it before. But the employment of columns induced a new feature—viz., a tendency in the larger units (_e.g._ divisions) to close on their centre—and presently before our eyes we saw a great gap opening out behind the enemy’s fighting line. The time for the final blow was close at hand. Our gunners, coming up under cover of the hills, were crushing the artillery of the enemy out in the plain, and had some attention to spare for his reserves. I saw a cavalry aide-de-camp leave the Staff of the Army Commander, who was close at hand, and I made tracks as fast as I could for some broken ground, where I hoped to be safe from the coming storm.