Abstract
Theory of the radial magnetic gradient of the sun based on the diamagnetic effect produced by ions spiralling about the impressed magnetic field.—The thermal ionization of the sun's atmosphere, free paths and velocities of thermal agitation of the molecules and ions all have such values that the diamagnetic effect is very large in the regions of the sun's atmosphere where abnomally large magnetic gradients are observed. Extrapolation of the diamagnetic effect into regions where there are no available experimental data shows that the magnetic field at the surface of the sun is several times the generally accepted value.