nd 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.

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