In the case of a flat plate all velocity profiles have the same limit of stability, namely U =0; in contrast with that, in the case of an arbitrary body shape, the individual velocity profiles have markedly different limits of stability, higher than for a flat plate with favourable pressure gradients,and lower with adverse pressure gradients. Consequently, in order to determine the position of the point of instability for a body of a given, prescribed shape, it isnecessary to perform the following calculations: