The gap between the British Fifth and Third Armies was filled by a scratch division eventually commanded by General Carey, who really deserves the credit for its exploits. There were no troops to be had, but American and Canadian engineers, cooks, chauffeurs, road workers, anything that walked on two legs, were picked up wherever they could be found, in ones, twos, and tens, armed with the first implements that came to hand, and rushed up to the gap on trucks, on horseback, on mule teams, on foot. Near by they found a machine gun school with plenty of guns and ammunition. Only a few of the men collected had ever handled a machine gun, but those who knew how fell to work in the crowded minutes of a battle on the outcome of which the fortunes of the world were at stake, and taught the rest how to shoot. For two days the detachment held the gap, which was at that time only a couple of miles wide. The commander then collapsed from exhaustion.

At this very instant, in the providential way often told in novels, appeared a dusty automobile; in it was General Carey looking for his troops. He was pressed into service by the scratch division and told the danger. An old South African soldier of the dare-devil type, afraid of nothing and full of resource, he took the situation in hand. For six days with very little eating and less sleeping, these cooks, chauffeurs, and engineers, men who had never maneuvered in their lives, armed merely with what they could pick up, and led by a general who had never seen them before, convinced the Germans that a great force of experienced troops held the position. They attacked here, rushed to a position a mile away, and attacked again. They lost ground constantly, were beaten time and again, but came back for more. They held the gap; the Germans did not get through. They saved the battle, and it will be a source of pride to many that a division of American engineers sent to France for very different work formed the backbone of this scratch army, and that a good many of the rest were American ambulance drivers. Others were Canadians, a people who fought throughout the war with a gallantry unsurpassed by any nation.

One dramatic feature of this tremendous offensive was warfare in the air on a scale never before attempted. Hundreds of Allied and German machines went out to combat in massed formation. They charged each other, laid down barrages of machine gun fire, swooped down upon advancing troops and annihilated them with a hail of bullets. The losses of men and machines were terrific: the latter fell in tens and dozens, some as the result of collisions, some with pilots killed, others in flames. For two days the battle raged as intensely in the air as on the ground. Then the Allied aviators won. Their victory was one of the vital factors slowing down the German drive and was certainly responsible for the German ignorance of the plights of Fayolles' and Carey's divisions.

But the magnitude of the defeat could not be concealed. The Allied line had been broken and patched up again; but it had bent and bulged repeatedly until more ground had been surrendered in a few days than the Allies had won in three years. The Germans were within a few miles of Amiens and well on the road toward the coast. The Allied reserves came up, however, and the German advance itself slowed down. They had outrun their artillery; they outran their supply trains with food and ammunition; flesh and blood could do only so much and at the end of a week the great rush was manifestly over.

Then in the first week of April, fresh German troops delivered the second blow upon the next sector of the British line around Arras. This was now the key to the entire British position. The line had bulged out so far to the south that if Arras should fall and the Third British Army under General Byng should be defeated, the whole line as far as the Channel must swing back. But to the astonishment of the Germans and the extraordinary joy of the Allies, General Byng's army held its ground and yielded nothing of consequence. Back went the Germans to work on the great bulge at Amiens, trying to push through the sides so they might safely advance further in the center.

Now in April came a great change. General Foch was appointed general of all the Allied armies. He was to command the British, the Americans, and the Italians as well as the French. He was to dictate all the moves of the campaign. This unity of command the Allies had hitherto declined to adopt for various reasons not necessary here to explain, but the great crisis compelled some sort of radical change and the appointment of one general seemed the best measure to take.

By direction of President Wilson, General Pershing offered General Foch the services of all American troops in France, to be used wherever and whenever he could. They were to be brigaded with the French and British troops and commanded by French and British generals. It was one of the wisest of the President's decisions and made the American troops at once available in the field. Our private soldiers were ready to fight, but our general staff and our artillery were not sufficiently experienced at that time to have taken the responsibility of a sector of the front at such a crisis. Probably they would have acquitted themselves well, but the risk would have been too great, for the Germans would have at once singled out that sector for a crushing attack, and the last week had shown that the British and French themselves, despite their experience and training, were not able to withstand the German thrusts. Reënforcements also were poured in from England, and arrangements were made at once in the United States to ship over to France as rapidly as possible the new army which had been training during the previous months. This was the great crisis of the war. Ready or not ready, let the men go to France; the work of Carey's scratch division had shown what could be done by intelligent but untrained men.

But the Germans gave the Allies no rest. On April 9 a great drive was begun against the Second British Army in the sector between Ypres and Arras. Having failed to dislodge Byng's army, the Germans proposed to bulge out the line above him and thus compel him to retire, and at the same time put the British army on the coast in such danger that they also would have to flee. The success was again substantial, although not so great as in the attack of March 21. A great hole was opened out and then considerably widened; the British were compelled to retire from ground which they had won during the previous three years at heavy cost in men. The net results of these attacks was to put the entire British line in the gravest peril.

And now, fortunately for the Allies, the Germans were compelled to pause for a month to organize a new effort. They had expected the first attack to demolish the British army. The moment it failed to do so, the amount of ground it occupied became an embarrassment to the Germans. They must rearrange their forces, rest their troops, and prepare again for a new thrust. They could not take so much time as they had taken before, but they must take more than they could afford, for the Allies also would have that period in which to prepare to meet the assault.

On May 27, the Germans began what is known as the battle for Paris. Down to the south of the great bulge they had made in March, they directed an attack, just west of the great city of Rheims, directly at Paris. Poison gas was used with especial freedom in this attack and a great concentration of troops and artillery. Once more the Allied line yielded. There were now three great bulges in the line. On June 9 the battle was begun along the river Oise to fill in the gap between the first bulge and this third bulge, but it was only partially successful. The Allied reserves had come up; Foch had had time to make his and the French and Americans threw back the Germans at more than one point.

Again the Germans paused and took time to prepare for the final and much advertised thrust which was this time to win the war. Using the great bulge just created to the west of Rheims, they proposed to move east from its side and also to attack from the north at the same time, thus striking the French and American armies in this sector on two sides at once. The success of either of these attacks would insure the success of the other, and both would mean the loss of Rheims and the withdrawal of that whole section of the line. Verdun would then be isolated and could be assailed from the rear. It might have to surrender and the whole French right wing could then be crumpled up. Or, if the German High Command preferred, Paris would be at their mercy and they could destroy the center of the French army. The British ought then to be assailed with ease.

Whether the Germans were too confident and made less competent preparations than before, because they believed the French army exhausted and demoralized, we do not know, but this supposedly greatest attack was the least successful of all. It was stopped almost at once; after three days it was clearly a failure, and on July 18 Foch delivered an Allied offensive which at once succeeded and which was to continue until the war was won. In March, the Germans had all but won the war; in April again it looked as if they might win it; in June the decision still was within their reach. One month later it became clear to the Allies that the Germans had lost; two months later victory was in sight; in three months victory was at hand. In four months after the Germans had been conceded in London and Paris to have an admirable chance of winning the war, they surrendered. No more extraordinary and rapid change is recorded in history.