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 primitive time, and an unexcelled thinness of the metal is the mark of a genuine Greek bronze statue. It can hardly be necessary to recollect the long story of the benefits of this kind which scientific knowledge has conferred upon art. Linear perspective was discovered by the artists themselves, by Leonardo and Dürer. The laws of reflection 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 ponderation. Aërial 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 naturalists, among them some of the first rank, have interested themselves 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 Müller, women of taste of all times are correct in the choice of their clothing;[1] 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 Müller, and others. These matters have been discussed by our fellow member, Herr Ernst von Brücke, in his Physiology of Colors for industrial art, and his Fragments from the Theory of the Fine Arts,[2] with such special skill as only the rare combination of the artistic culture acquired in his father's studio with his own physiological knowledge could make possible. Chevreul pursued similar aims in France. Not less did Prof, von Helmholtz embody his profound 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 objects stand to those which the painter controls, and showed what means he could employ to overcome the difficulties growing out of them.[3] By imitation of the irradiation recognized by him in
