In an etching, Rembrandt could leave a piece of white paper for the spot of highest sunlight, and carry out all the gradations of tone in black and white, until he reached the spot of darkest shadow.  A painted landscape he indicated in the same way by varying shades of dull brown.  In all of them you seem to feel the interposition of the air between you and the distant horizon at which you are looking.  What else is there?  At each point in the picture the air modifies the distinctness with which you can see the objects.  This consciousness of air in a picture of low horizon is a very difficult thing to describe and explain.  We know when it is there and when it is not.  It has to be seen, to be enjoyed, and recorded.  Holbein painted Edward VI. standing, so to speak, in a vacuum.  Every line of his face is sharply defined.  In real life air softens all lines, so that even the edge of a nose in profile is not actually seen as a sharp outline.  The figures in Richard II.’s picture stand in the most exhausted vacuum, but Hubert van Eyck had already begun to render the vision or illusion of air in his ‘Three Maries.’  In this respect he had learnt more than the early painters of the Italian Renaissance; but Raphael and the Venetians, especially Giorgione and Titian, sometimes bathed their figures in a luminous golden atmosphere with the sun shining through it.

The Dutch painters carried this still further, particularly in their pictures of interiors and landscapes.  It is the atmosphere in the rooms that makes Peter de Hoogh’s portrayal of interiors so wonderful.  In our little picture the light coming through the window makes the air almost golden.  When this painting of air and tone is set forth by the exquisite colour of Peter de Hoogh, you see this kind of Dutch achievement at its best.  Cuyp’s love of sunshine is rare among Dutch landscape painters.  He suffuses his skies with a golden haze that bathes his kin and kine alike in evening light.  In our picture you can feel the great height of the sky and the depth of the air between the foreground and the horizon.  The rendering of space is excellent.  But Cuyp has not been content with the features of his native Holland.  He has put an imaginary mountain in the distance and a great hill in the foreground.  It is certainly not a view that Cuyp ever saw in Holland with his own eyes.  He thought that the mountain’s upright lines were good to break the flatness; and the finished composition, if beautiful, is its own excuse for being.

[Illustration:  LANDSCAPE WITH CATTLE From the picture by Cuyp, in the Dulwich Gallery]