2. It is not possible for us to forecast whether the above prerequisites of success will be realised. Too much importance should not be attached to past experience since the policy, scale and methods of attack have changed. 3. So long as visual aiming is essential to effective night attack, weather conditions will introduce an unpredictable element into all estimates. If it became possible to locate by other methods a target area suited to the force available, both the efficacy and the predictability of night operations would be greatly increased.