Having elected from a very early time to paint in monochrome, Chinese painters were led by the nature of this medium to seek to express atmospheric perspective by means of tone values and harmony of shading instead of by color. Thus they were familiar with chiaroscuro before the European painters. Wang Wei established the principles of atmospheric perspective in the eighth century. He explains how tints are graded, how the increasing thickness of layers of air deprives distant objects of their true coloring, substituting a bluish tinge, and how forms become indistinct in proportion as their distance from the observer increases. His testimony in this respect is similar to that of Leonardo da Vinci in his "Treatise on Painting." [2] The Chinese terms are _Li Chou_ for a vertical painting and _Hêng P'i_ for a horizontal painting.--TRANSLATOR. [Illustration: PLATE III. KWANYIN. EIGHTH TO TENTH CENTURIES Painting brought from Tun-huang by the Pelliot Expedition. The Louvre, Paris.] III. DIVISION OF SUBJECTS The Chinese divide the subjects of painting into four principal classes, as follows: Landscape. Man and Objects. Flowers and Birds. Plants and Insects. Nowhere do we see a predominant place assigned to the drawing or painting of the human figure. This alone is sufficient to mark the wide difference between Chinese and European painting. The exact name for _Landscape_ is translated by the words _mountain and water picture_. They recall the ancient conception of Creation on which the Oriental system of the world is founded. The mountain exemplifies the teeming life of the earth. It is threaded by veins wherein waters continuously flow. Cascades, brooks and torrents are the outward evidence of this inner travail. By its own superabundance of life, it brings forth clouds and arrays itself in mists, thus being a manifestation of the two principles which rule the life of the universe.