IN this issue appears a summary of a paper prepared by two of the research workers of the National Advisory Committee for Aeronautics which is most opportune. A number of minds, both among designers and scientists, have been exercising themselves with thoughts as to what may be the effect on a modern aeroplane of meeting a vertical current, commonly referred to as a “bump.” There are those who believe, or at any rate wonder, whether the ever‐increasing speeds at which aeroplanes fly may not give rise to added danger from this cause. They argue that the higher velocity at which the aeroplane meets the bump results in the impact of the blow received on the structure being accentuated by the reduction of time over which it is felt, with a consequent increase in the effects. There is, on the other hand, the directly opposite view that the aeroplane of higher speed changes its angle of incidence, and therefore yields, more quickly, and so the force of the impact is lessened.