"And I think I am supported in this feeling by the unanimous practice, if not the confessed opinion, of all artists. The painter of portrait _is unhappy without his conventional white stroke under the sleeve_, or beside the arm-chair; the painter of interiors feels like a caged bird unless he can throw a window open, or set the door ajar; the landscapist dares not lose himself in forest without a gleam of light under its farthest branches, nor ventures out in rain unless he may somewhere pierce to a better promise in the distance, or cling to some closing gap of variable blue above."--(P. 39.) But if an open window, or "that conventional white stroke under the sleeve," is sufficient to indicate the Infinite, how few pictures there must be in which it is not indicated! and how many "a tame and trivial theme" must have been, by this indication, exalted and rendered impressive! And yet it seems that some very celebrated paintings want this open-window or conventional white stroke. The Madonna della Sediola of Raphael is known over all Europe; some print of it may be seen in every village; that virgin-mother, in her antique chair, embracing her child with so sweet and maternal an embrace, has found its way to the heart of every woman, Catholic or Protestant. But unfortunately it has a dark background, and there is no open window--nothing to typify infinity. To us it seemed that there was "heaven's light" over the whole picture. Though there is the chamber wall seen behind the chair, there is nothing to intimate that the door or the window is closed. One might in charity have imagined that the light came directly through an open door or window. However, Mr Ruskin is inexorable. "Raphael," he says, "_in his full_, betrayed the faith he had received from his father and his master, and substituted for the radiant sky of the Madonna del Cardellino the chamber wall of the Madonna della Sediola, and the brown wainscot of the Baldacchino." Of other modes in which the Infinite is represented, we have an instance in "The Beauty of Curvature."