What are the other abiding features of landscape? Well, shadow or half-light--light partially obscured by opaque bodies. It could be used as a contrast and by cunning application could be made to enhance the luminosity of full light. Moreover, interior depth and penetration could be obtained with it. Best of all, its uncertainty lent itself to suggestiveness and the mystery of things half seen. Inness was greatly in love with it. Many of his late canvases are called “vague” or sometimes “swampy,” because they are saturated with shadow masses out of which loom or glow mysteriously half-seen forms and colors. Martin made no such use of it as Inness, though many of his foregrounds are in shadow through which one looks to a lightened middle distance or sky. He was very fond of a light broken by being filtered through thin clouds, and he carried this out by employing a diffused thin shadow such as obtains under broken light. It is not often that one meets with dark shadows in his later pictures. He seemed to shy at anything like blackness, and in one of his pictures now in the Metropolitan Museum--the “View on the Seine”--the luminosity is so marked that the picture has the look of a water-color drawing. It was not the black and the “woolly” in Corot that he loved but the luminous and the radiant. Another omnipresent and universal feature of landscape is color. It is an emanation of light, is, in fact, no more than its dispersed beams. If the light is direct and unclouded, the color will leap to very high pitches, such as we see in the landscapes of Inness or the Algerian scenes of Delacroix or Regnault or Fromentin; if the light comes from below the horizon and is reflected down to earth from the upper sky, the color will be subdued in mellow tones of saffron, rose, and grays such as we see in the dawns of Corot; if the light comes from above the horizon at sunset and is filtered through filmy forms of cumulo-stratus clouds, the color will be delicate broken tones of gold, azure, sad grays such as we see in the “Honfleur Light” or the “Criquebœuf Church” of Martin. He revelled in these subdued tones of broken light. They were not only the eternal coloring of nature but they were the means wherewith he expressed his own sentiment or feeling about nature.