346 Professor Tyndall [March 19, 



of fine smoke from the foresters' cottages to rise high into the air. 

 He would thus have an opportunity of seeing the upper portion of 

 the column projected against bright clouds, and the lower portion 

 against dark pines, the brownish yellow of the one and the blue of 

 the other being strikingly and at once revealed. He was able to 

 produce artificially at will the colours which he had previously 

 observed in nature. He noticed that when certain bodies were incor- 

 porated with glass this substance also played a double part, appearing 

 blue by reflected and yellow by transmitted light.* 



The action of turbid media was to Goethe the ultimate fact — the 

 TJrplidnomen — of the world of colours. " We see on the one side Light 

 and on the other side Darkness. We bring between both Turbidity, 

 and from these opposites develop all colours." As long as Goethe 

 remained in the region of fact his observations are of permanent 

 value. But by the coercion of a powerful imagination he forced his 

 turbid media into regions to which they did not belong, and sought 

 to overthrow by their agency the irrefragable demonstrations of 

 Newton. Newton's theory, as known by everybody, is that white 

 light is composed of a multitude of differently refrangible rays, 

 whose coalescence in certain proportions produces the imj^ression of 

 white. By prismatic analysis these rays are separated from each 

 other, the colour of each ray being strictly determined by its re- 

 frangibility. The experiments of Newton, whereby he sought to 

 establish this theory, had long appealed with overmastering evi- 

 dence to every mind trained in the severities of physical investiga- 

 tion. But they did not thus appeal to Goethe. Accepting for the 

 most part the experiments of Newton, he rejected with indignation 

 the conclusions drawn from them, and turned into utter ridicule the 

 notion that white light possessed the composite character ascribed to 

 it. Many of the naturalists of his time supported him, while among 

 philosophers Schelling and Hegel shouted in acclamation over the 

 supposed defeat of Newton. The physicists, however, gave the poet 

 no countenance. Goethe met their scorn with scorn, and under his 

 lash these deniers of his theory, their Master included, paid the 

 penalty of their arrogance. 



How, then, did he lay down the lines of his own theory ? How, 

 out of such meagre elements as his yellow, and his blue, and his 

 turbid medium, did he extract the amazing variety and richness of the 

 Newtonian spectrum? Here we must walk circumspectly, for the 

 intellectual atmosphere with which Goethe surrounds himself is by 

 no means free from turbidity. In trying to account for his position, 

 we must make ourselves acquainted with his salient facts, and en- 

 deavour to place our minds in sympathy with his mode of regarding 

 them. He found that he could intensify the yellow of his transmitted 

 light by making the turbidity of his medium stronger. A single 



* Beautiful and iiibtructive samples of such glass are to be seen in the A^'niee 

 (ilass Company's shop, No. 30, St. James's Street. 



