From the defensive point of view our line was very strong, and the trenches, particularly at the eastern end, very good, deeply blasted in the rock. The wooded ridge, running close behind our front line all the way, completely hid from the enemy all movement in our rear. He could get no observation here except by aircraft. Even movements in our front line, owing to the trees, were largely invisible at a distance, and, owing to the lie of the ground, large parts of No Man's Land could be seen from our own trenches, but from nowhere in the enemy's lines, with the result that we were able to post machine guns, trench mortars and even, for a short time, a field battery there, without being detected, until these weapons had served their immediate purpose. Our systems of transport, supply and reliefs of the troops in the line could, therefore, be carried out at any hour of the day or night with almost complete disregard of the enemy. His intermittent shelling of the roads was perfectly blind and haphazard and seldom did us any damage. He, on the other hand, was in a very undesirable situation. Not only was his front line all the way in full view from our various ground O.P.'s, but a long stretch of flat country several miles broad behind his front line was equally in view. Only a few small folds in the ground were invisible from all points along our ridge. We could see also most of the nearer slopes of the northern ridge, though here the thick woods and breaks in the hillside gave him greater opportunities for concealment. Taking into account, therefore, ground observation only, we had him at a tremendous disadvantage. He dared not move nor show himself in daylight behind his line, and was compelled to carry out all his supply and troop movements at night, or during fogs that might lift at any moment. One French Battery did no other work except sweep up and down his roads throughout the hours of darkness, and it is obvious that the probable damage done in this way was far greater than anything he could hope to do to us. Taking into account the possibilities of observation from the air, the balance in our favour became even greater. We had a strong superiority in the air, whenever it was worth our while to enforce it, partly because our airmen were individually superior to the Austrians, and partly because we had more and better machines. Our pilots often flew over the northern ridge, both to observe and to bomb, but the enemy seldom crossed the southern ridge. His anti-aircraft Batteries were, however, at least as good as ours, and, in my opinion, better.