4 This direction can be established with sufficient exactitude by holding a very thin object right in front of the prism and marking with a stretched thread the direction which leads from the object to its shadow on the screen. The colour-producing edge must then be introduced from either side so that it just touches the thread. 5 The difference in character of the various parts of the spectrum, as described above, comes out particularly impressively if for capturing the colour-phenomenon one uses instead of a flat white surface, a clear crystal of not too small size, or else a cluster of crystals - moving it slowly along the coloured band from one end to the other. (I am indebted to Fr. Julius, teacher of Natural Science at the Free School in The Hague, for this suggestion.) PART III Towards a New Cosmosophy CHAPTER XIX The Country in which Man is not a Stranger I question not my Corporeal or Vegetative Eye any more than I question a window concerning sight. I look through it and not with it. WILLIAM BLAKE. (a) INTRODUCTORY NOTE A fundamental achievement along our path of study was the recognition that a force of levity exists, polar to that of gravity, and that these two together represent a primary polarity in nature which in turn is the source of nature's manifold secondary polarities. In the last part of these studies a vista opened up of an inner differentiation of levity itself into warmth, light, chemical action and the formative activity of life. Our next task will be to develop a clearer conception of these four modes of action of levity. In undertaking this task, however, we shall have to extend our observations of nature beyond the frontier that can be reached by using only what we can learn from Goethe. It is here that Rudolf Steiner comes to our aid by what he was able to impart through his researches in the realm of the supersensible itself. This turning to information given by another mind, whose sources of knowledge are beyond our own immediate reach, seems at first sight to be incompatible with the principles guiding all our studies hitherto; for in gaining insight into the How and Whence of a phenomenon of the sense-world we have up to now admitted only what is yielded by an observation of the phenomenon per se (though with the aid of the 'eye of the spirit') and of other phenomena related to it. This is what we have called 'reading in the book of nature', and we have found it to be the method on which a science aspiring to overcome the onlooker-picture of the universe must be based. So we must first make sure that the step we now propose to take does not violate this principle. *