Photos 5 and 6, Photographs of barrage. These seem to be photos of preliminary barrages that would have been fired to test the British plans and inflict losses on the Germans. The upper photo shows the field artillery barrage, in both its depth and density; apparently some of the shells used were smoke shells. The lower photo shows some of the howitzer element of the barrage, moving along German communications trenches to block reinforcements moving forward or the trench garrison from retreating.

Source: WO316