The object of that offensive was threefold:
(ii.) To assist our allies in the other theatres of war by stopping any further transfer of German troops from the western front.
(iii.) To wear down the strength of the forces opposed to us.
[Sidenote: Enemy attempts at interference.]
While my final preparations were in progress the enemy made two unsuccessful attempts to interfere with my arrangements. The first, directed on May 21, 1916, against our positions on the Vimy Ridge, south and southeast of Souchez, resulted in a small enemy gain of no strategic or tactical importance; and rather than weaken my offensive by involving additional troops in the task of recovering the lost ground, I decided to consolidate a position in rear of our original line.
The second enemy attack was delivered on June 2, 1916, on a front of over one and a half miles from Mount Sorrell to Hooge, and succeeded in penetrating to a maximum depth of 700 yards. As the southern part of the lost position commanded our trenches, I judged it necessary to recover it, and by an attack launched on June 13, 1916, carefully prepared and well executed, this was successfully accomplished by the troops on the spot.
Neither of these enemy attacks succeeded in delaying the preparations for the major operations which I had in view.
These preparations were necessarily very elaborate and took considerable time.
[Sidenote: Shelter and communication facilities prepared.]
Vast stocks of ammunition and stores of all kinds had to be accumulated beforehand within a convenient distance of our front. To deal with these many miles of new railways--both standard and narrow gauge--and trench tramways were laid. All available roads were improved, many others were made, and long causeways were built over marshy valleys. Many additional dugouts had to be provided as shelter for the troops, for use as dressing stations for the wounded, and as magazines for storing ammunition, food, water, and engineering material. Scores of miles of deep communication trenches had to be dug, as well as trenches for telephone wires, assembly and assault trenches, and numerous gun emplacements and observation posts.
Important mining operations were undertaken, and charges were laid at various points beneath the enemy's lines.