Back at home, he strove to recollect the theory of Newton as it was being taught in schools and universities - namely, that 'colours in their totality are contained in light'. Hitherto he had had no occasion to doubt the correctness of this theory. Like everyone else, he had heard it expounded in lectures as an incontestable result of empirical observation, though without this ever having been shown to him by way of experiment. He convinced himself by consulting a manual that his recollection was correct, but at the same time he found that the theory there set forth gave no help in answering his questions.5 So he decided to examine the phenomena for himself.
For this purpose he borrowed a set of prisms from a friend living in near-by Jena, the physicist, Büttner. Since, however, he had at that time no opportunity of arranging a dark chamber on Newton's lines, where the necessary ray of light from a tiny hole in the window-covering was sent through a prism, he postponed the whole thing, until in the midst of all his many other interests and duties it was forgotten. In vain Büttner pressed many times for the return of the prisms; at last he sent a mutual acquaintance with the injunction not to return without them. Goethe then searched for the long-neglected apparatus and determined to take a rapid glance through one of the prisms before he gave them back.
He recalled dimly his pleasure as a boy at the vision of the world given him through a bit of similarly shaped glass. 'I well remember that everything looked coloured, but in what manner I could no longer recollect. I was just then in a room completely white; remembering the Newtonian theory, I expected, as I put the prism to my eye, to find the whole white wall coloured in different hues and to see the light reflected thence into the eye, split into as many coloured lights.
'But how astonished was I when the white wall seen through the prism remained white after as before. Only where something dark came against it a more or less decided colour was shown, and at last the window-bars appeared most vividly coloured, while on the light-grey sky outside no trace of colouring was to be seen. It did not need any long consideration for me to recognize that a boundary or edge is necessary to call forth the colours, and I immediately said aloud, as though by instinct, that the Newtonian doctrine is false.'
For Goethe, there could be no more thought of sending back the prisms, and he persuaded Büttner to leave them with him for some time longer.
Goethe adds a short account of the progress of the experiments he now undertook as well as of his efforts to interest others in his discovery. He makes grateful reference to those who had brought him understanding, and who had been helpful to him through the exchange of thoughts. Among these, apart from Schiller, whom Goethe especially mentions, we find a number of leading anatomists, chemists, writers and philosophers of his time, but not a single one of the physicists then active in teaching or research. The 'Guild' took up an attitude of complete disapproval or indifference, and so have things remained till a hundred years after his death, as Goethe himself prophesied.
One of the first systematic pieces of work which Goethe undertook in order to trace the cause of the Newtonian error was to go through Book I of Newton's Optics, sentence by sentence, recapitulate Newton's experiments and rearrange them in the order which seemed to him essential. In so doing he gained an insight which was fundamental for all future work, and often proved very beneficial in the perfecting of his own methods. His examination of the Newtonian procedure showed him that the whole mistake rested on the fact that 'a complicated phenomenon should have been taken as a basis, and the simpler explained from the complex'. Nevertheless, it still needed 'much time and application in order to wander through all the labyrinths with which Newton had been pleased to confuse his successors'.
*
It seems a small thing, and yet it is a great one, which Goethe, as the above description shows, discovered almost by chance. This is shown by the conclusions to which he was led in the systematic prosecutions of his discovery. An account of them is given in his Beiträge zur Optik,6 published in 1791, the year in which Galvani came before the public with his observations in the sphere of electricity.
Goethe describes in this book the basic phenomena of the creation of the prismatic colours, with particulars of a number of experiments so arranged that the truth he had discovered, contrary to Newton's view, comes to light through the very phenomena themselves. Only much later, in the year 1810, and after he had brought to a certain conclusion four years previously the researches which he had pursued most carefully the whole time, did he make public the actual masterpiece, Entwurf einer Farbenlehre.7 (An English translation of the didactic part appeared about ten years after Goethe's death.)