References to previous papers by the author show that his ideas on typhoon origin and structure contain the following main elements: (a) Strong surface convergence of two or more humid air streams. (b) Strong upward convection in a rather narrow ring near typhoon center, giving a warm inner core, and conditions favoring a modified Rankine vortex. (c) The formation of an upper front, roughly funnel-shaped. (d) Possible divergence aloft, especially a fast upper current to dispose of the rising core air and partially at least controlling the pressure gradient and size of the convection ring. These ideas are subjected to approximate mathematical treatment, giving satisfactory magnitudes for pressure gradients and proper shape of pressure curve. A short discussion is given of what are considered the most essential elements determining typhoon origin and structure. References to previous papers by the author show that his ideas on typhoon origin and structure contain the following main elements: (a) Strong surface convergence of two or more humid air streams. (b) Strong upward convection in a rather narrow ring near typhoon center, giving a warm inner core, and conditions favoring a modified Rankine vortex. (c) The formation of an upper front, roughly funnel-shaped. (d) Possible divergence aloft, especially a fast upper current to dispose of the rising core air and partially at least controlling the pressure gradient and size of the convection ring. These ideas are subjected to approximate mathematical treatment, giving satisfactory magnitudes for pressure gradients and proper shape of pressure curve. A short discussion is given of what are considered the most essential elements determining typhoon origin and structure.