 Here he was put on the problem of devising a useful bombsight that did not require manual calculations or a stopwatch to estimate the wind speed.The result was his Drift Sight, which used a small bar that was aligned with the motion of objects on the ground to measure the wind.He then greatly expanded on this design in his Course Setting Bomb Sight (CSBS) in 1917, introducing the first system to allow bomb runs from any direction, instead of just up or down the wind line.