When phenomenology was introduced as a new science by Husserl its methods were applied first to objects of logic. Later phenomenological investigation expanded gradually to the fields of psychology, ethics, esthetics, and sociology (Scheler, Pfänder, Hildebrand a.o.). More rarely, objects of the natural sciences have been treated phenomenologically. Scattered indications of this kind are to be found in authors who do not belong to the most intimate circle of Husserl's school (Helmut Plessner, Kurt Goldstein, Walter Frost, E. Buenning). Extensively, however, the phenomenological method has been applied to objects of the natural sciences once only, namely by Hedwig Conrad-Martius, a favorite pupil of Husserl's, in her Realontologie (Ontology of Reality) and Farben (Colors). Yet this less known branch of phenomenology is particularly interesting. Husserl stressed the basic difference between phenomenological ideation (Wesensschau) on the one hand and psychological introspection and description of the immediate data of awareness on the other. The peculiarity and scientific productivity of phenomenological method, therefore, can be studied best in a field which is as far removed from psychology as possible. We shall try to analyze the papers of Conrad-Martius more fully and shall refer to other authors occasionally as illustrations.