7s8 THE POPULAR SCIENCE MONTHLY. 



of a thing so primitive as the preparation of pigments or of certain 

 knacks in casting ; the less so because, as is well known, our colors 

 are in a remarkable way poorer than those of an unscientific primi- 

 tive time, and an unexcelled thinness of the metal is the mark of a 

 genuine Greek bronze statue. It can hardly be necessary to recol- 

 lect the long story of the benefits of this kind which scientific knowl- 

 edge has conferred upon art. Linear perspective was discovered 

 by the artists themselves, by Leonardo and Diirer. The laws of re- 

 flection and shadow-construction, which were still unknown to the 

 ancient painters, if we may judge from the Pompeiian Narcissus- 

 pictures, followed. In the representation of the rainbow, which 

 had better be left unpainted, many and serious mistakes have been 

 made, notwithstanding the teachings of optics. Statics furnished 

 the sculptor important instruction concerning what is called pon- 

 deration. Aerial perspective owes its development, again, to the 

 painters, particularly to those of northern lands. 



The advance of science has added to those ancient helps much 

 of importance, although it is not so fundamental, and many natu- 

 ralists, among them some of the first rank, have interested them- 

 selves in making the new knowledge accessible to artists. The 

 great masters of past centuries were guided by their feelings to 

 the proper selection of colors, as, according to Johannes Miiller, 

 women of taste of all times are correct in the choice of their cloth- 

 ing ; * and the Oriental carpet- weavers are not behind them. But 

 the significance of such unconscious success could be perceived 

 only after the subjective physiology of the sense of sight had been 

 created by the older Darwin, Goethe, Purkinje, Johannes Miiller, 

 and others. These matters have been discussed by our fellow- 

 member, Herr Ernst von Briicke, in his Physiology of Colors for 

 industrial art, and his Fragments from the Theory of the Fine 

 Arts,t with such special skill as only the rare combination of the 

 artistic culture acquired in his father's studio with his own physio- 

 logical knowledge could make possible. Chevreul pursued similar 

 aims in France. Not less did Prof, von Helmholtz embody his pro- 

 found knowledge of physiological optics in public lectures in the 

 service of art, which owes to him likewise his fruitful conclusions 

 concerning the nature of musical harmony. He explained among 

 other things the relation in which differences of luster of real ob- 

 jects stand to those which the painter controls, and showed what 

 means he could employ to overcome the difiiculties growing out 

 of them. I By imitation of the irradiation recognized by him in 



* Handbuch der Physiologic des Menschen, etc. Vol. ii, Part II, Coblentz, 1838, 

 p. 375. 



f Physiologie der Farben, etc. First edition, Leipsie, 1866; second edition, 1887, 

 Bruchstiicke, etc., Leipsie, 1877. 



\ Optisches ueber Malerei. Vortrage und Reden, vol. i, Brunswick, 1884. Concerning 



