Klange (Sounds) and Uber das Geistige in der Kunst (Concerning the Spiritual in Art) were published in 1912. Kandinsky recalled the preceding summer was intolerably hot. At Murnau he could not breathe; he could not, strange to say, even sweat. There were psychological portents, too: divorce, not only from his wife, but from certain Munich colleagues, who declared his work had grown too abstract. 'All at once,' according to Kandinsky, 'nature looked white to me; the white (profound silence-full of possibilities) was everywhere and was visibly spreading.'

One could be forgiven for supposing Kandinsky had succumbed to the pressures. But it was quite otherwise. Kandinsky had already outlined the theoretical basis of abstraction in Uber das Geistige in der Kunst, written mainly in 1910. There he had introduced his 'principle of inner necessity'. The painter's object was not the representation of external forms and colours, but, through them, to express an inner, creative spirit, 'The white, fertilising ray'. What he now recognised at Murnau was the truth of his thesis: the personal intuition of a previously intellectual proposition. In effect, Kandinsky explained, he realised that white, which he had formerly regarded with indifference, because it was characterless, for that very reason held the key to the future. Between white and its negative, black, all things were possible. Freed of all constraint to represent the material objects of experience, line and colour might spawn forms of their own, abstract forms corresponding to an 'inner necessity'. The same approach ...