44 ox GOETHE'S SCIENTIFIC RESEARCHES. 



unacquainted with the geometrical relations by which the most 

 favourable positions of them are determined. In other experi- 

 ments on the separation of simple coloured light by means of 

 prisms alone, Goethe's objections are not quite groundless, inas- 

 much as the isolation of single colours cannot by this means be 

 so effectually carried out, that after refraction through another 

 prism there are no traces of other tints at the edges. A com- 

 plete isolation of light of one colour can only be effected by 

 very carefully arranged apparatus, consisting of combined 

 prisms and lenses, a set of experiments which Goethe postponed 

 to a supplement, and finally left unnoticed. When he complains- 

 of the complication of these contrivances, we need only think 

 of the laborious and roundabout methods which chemists must 

 often adopt to obtain certain elementary bodies in a pure form ; 

 and we need not Ije surprised to find that it is impossible to 

 solve a similar problem in the case of light in the open air in a 

 garden, and with a single prism in one's hand. 1 Goethe must, 

 consistently with his theory, deny in toto the possibility of 

 isolating pure light of one colour. Whether he ever experi- 

 mented with the proper apparatus to solve the problem remains 

 doubtful, as the supplement in which he promised to detail 

 these experiments was never published. 



To give some idea of the passionate way in which Goethe, 

 usually so temperate and even courtier-like, attacks Newton, I 

 quote from a few pages of the controversial part of his work 

 the following expressions, which he applies to the propositions 

 of this consummate thinker in physical and astronomical 

 science- -' incredibly impudent' ; ' mere twaddle' ; ' ludicrous ex- 

 planation' ; ' admirable for school-children in a go-cart' ; ' but I 

 see nothing will do but lying, and plenty of it.' 2 



1 I venture to add that 1 am acquainted with the impossibility of decom- 

 posing or changing simple coloured light, the two principles which form the 

 basis of Newton's theory, not merely by hearsay, but from actual observation, 

 having been under the necessity in one of my own researches of obtaining light 

 of one colour in a state of the greatest possible purity. (See I'oggendorfTs- 

 Annulet,, vol. Ixxxvi. p. f>01, on Sir D. Brewster's Xtw 'Analysis of Sunlight.) 



8 Something parallel to this extraordinary proceeding of Goethe's may be 

 found in Hobbes's attack on Wallis. TK. 



