The Third Corps was to operate on the front of one Division, the 58th, which, pivoting its left upon the Corbie—Bray road, was to advance its right—in sympathy with the advance of the left of the Australian Corps—until it rested upon the river about one mile downstream from Etinehem. It was a movement the success of which was rendered promising by the nature of the ground and the disorganized condition of the enemy between the Ancre and the Somme.

As regards my right flank, this was to rest as stated upon the main railway. The Canadian Corps, of four Divisions, would take over from the French a frontage of about 6,000 yards and deliver a thrust parallel to and south of the railway, in the direction of Caix and Beaucourt, and would aim at the seizure of the important Hill 102, immediately to the west of the latter locality. At no time did any question of the security of my right flank furnish me with any cause for anxiety; the prowess of the Canadian Corps was well known to all Australians, and I knew that, to use his own expressive vernacular, it was General Currie's invariable habit to "deliver the goods."

The comprehensive project thus outlined at the conference of July 21st involved, as a preliminary step, a far-reaching redisposition of very large bodies of troops over a very wide front. With the readjustment of the boundaries between the Third and Fourth British Armies we are not particularly concerned, because this affected a region, north of the Ancre, which lay well outside of the battle area. Nor did the internal readjustment of the northern part of the Fourth Army front present any difficulty, as it meant nothing more than a routine "relief" by the 58th Division of the Fifth Australian Division which was at this juncture holding that part of my Corps sector which lay between the Somme and the Ancre.

But the southern half was a very different matter. The First French Army was to give up to the British a section of about four miles, extending from Villers-Bretonneux to Thennes. This was ultimately to be taken over by the Canadian Corps as a battle front, but that Corps still had two of its Divisions in the line in the neighbourhood of Arras.

Moreover, it was of the utmost importance to conceal from the enemy until the last possible moment any change in our dispositions. This meant concealing them from our own troops also, because the loss by us of a single talkative prisoner would have been sufficient to disclose to the enemy at least the suspicion, if not the certainty, that an attack was in preparation.

After examining the problem and discussing several alternative solutions, it was ultimately decided at this conference that, five or six days before the date fixed for the attack, the French would be relieved in this sector by a Division, not of Canadians, but of Australians; that under cover of and behind this Australian Division, the Canadian Corps would come in from the north, and would proceed to carry out its battle preparations; and finally that the actual appearance of Canadian troops in the front line would not ensue until three days before the battle.

During the preceding two days, the Australian troops would be gradually withdrawn from the sector, leaving only one Brigade in occupation of the line, to be backed up by the incoming Canadians in the unexpected contingency of an attack by the enemy. This last Brigade would quietly melt away, leaving the Canadians in full possession of the field.

It was hoped that, during the days of the temporary Australian occupation of the sector, nothing would happen which might disclose to the enemy that the French had left it; and even if we were to have the misfortune to lose from this sector any Australian prisoners to the enemy, it was further hoped that, if kept in total ignorance of the inflow of Canadians, such prisoners would be unable to make any embarrassing disclosures. The dénouement, which will be told later, showed that this judgment of possibilities was a shrewd one, and that such precautions were not taken in vain.

At this period of the war, large numbers of Americans had already arrived in France, but only few of them were yet ready to take their places in the line of battle. The time had not yet arrived, therefore, when, by taking over large sections of the Western front they could help to shorten the French and British frontages. The British front was, therefore, still so extended that the mobile reserve Divisions at the disposal of the Field Marshal were few.