ABSTRACT
In the case of a luminous body like the sun, the intensity of the radiation emitted from any point is not uniform in all directions, but is governed by the well-known cosine law, sometimes known as Lamberts law. In the course of experiments on the magnetic deflexion of the rays emitted by the active deposit of radium, a very peculiar photographic effect was observed. This distribution of the intensity of the radiation for the radioactive sphere and cylinder is very different from that which would be observed if the photographs were taken by the luminous rays from a white-hot sphere or cylinder. Theoretically, the distribution should be quite different if the radiation comes from a thick instead of a thin layer of radioactive matter. It is difficult to obtain such radioactive sources in definite geometrie form. The rays from a wire about 15 cm long and 05 mm in diameter, made strongly active by exposure in the radium emanation.
