Most of our pre-arranged counter-battery shoots were carried out with aeroplane observation against enemy Batteries situated in the thick woods on the slopes of the northern ridge, the airman flying backwards and forwards over the target and sending us his observations by wireless. But it was often necessary to spend more than half of the four hundred rounds allotted to a normal counter-battery shoot in destroying the trees round the target, before the airman could get a good view of it. Flying, however, was always difficult on the Plateau, especially during the winter, and more difficult for our men than for theirs, since there were no feasible landing-places behind our lines. Our nearest aerodromes were down on the plain, and a big expenditure of petrol was required to get the airman up the mountains and actually over the Plateau, and also to get him down again. The time during which he could keep in the air for observation was, therefore, very limited. Weather conditions on the Plateau, moreover, were often very unfavourable for flying even in the spring and summer. The practical importance of our superiority in the air was thus smaller than might have been expected. From the defensive point of view, then, our position was pretty strong. But the sector was important and might at any time become critical, and much depended upon its successful defence. For the mountain wall that guarded the Italian plain had been worn very thin in this neighbourhood by the Austrian successes of last year. An Austrian advance of another few miles would bring the enemy over the edge of the mountains, with the plain beneath in full view. Further defence would then become extremely difficult and costly, and the whole situation, as regards relative superiority of positions and observation, now so greatly in our favour, would be more than reversed. We were too near the edge to have any elbow room or freedom of manoeuvre. Our present positions were almost the last that we could hope to hold without very grave embarrassment. It would have seemed evident, then, that to obtain more elbow room and security, we should not be content with a defensive policy, but should aim at gaining ground and thickening the mountain wall by means of an early local offensive, even if larger operations were not yet practicable.