Responses of the Proximal Retinal Pigment of the Isolated Crustacean Eyestalk to Light and to Darkness.

determination of thespanwise variation of moment distribution and indicates that the effect of finite span modifies the zero lift properties which the two-dimensional theory predicts. It is thought that the idea underlying the proposed two-equation procedure, which may be extended to an n-equation procedure, will also be useful in other problems of lifting-surface theory. Summary.-The steady motion of a rectangular lifting surface in incompressible flow is considered, with the following two objectives. (1) A modified derivation is given of Weissinger's improvement of Prandtl's lifting-line theory. (2) The integral equation of lifting-line theory (and Weissinger's improvement) for the spanwise variation of lift intensity is generalized to two simultaneous integral equations for lift intensity and moment intensity. In so doing certain difficulties of lifting-line theory with reference to behavior at and near tip sections are substantially ameliorated. The two-equation procedure of this paper is shown to be applicable to a problem which is outside the scope of the lifting-line equation.