though it be, affiliates it with the opposite or time pole. Painting occupies a middle position, since in it space instead of being actual has become ideal--three dimensions being expressed through the mediumship of two--and time enters into it more largely than into sculpture by reason of the greater ease with which complicated action can be indicated: a picture being nearly always time arrested in midcourse as it were--a moment transfixed. In order to form a just conception of the relation between music and architecture it is necessary that the two should be conceived of not as standing at opposite ends of a series represented by a straight line, but rather in juxtaposition, as in the ancient Egyptian symbol of a serpent holding its tail in its mouth, the head in this case corresponding to music, and the tail to architecture; in other words, though in one sense they are the most-widely separated of the arts, in another they are the most closely related. Music being purely in time and architecture being purely in space, each is, in a manner and to a degree not possible with any of the other arts, convertible into the other, by reason of the correspondence subsisting between intervals of time and intervals of space. A perception of this may have inspired the famous saying that architecture is _frozen music_, a poetical statement of a philosophical truth, since that which in music is expressed by means of harmonious intervals of time and pitch, successively, after the manner of time, may be translated into corresponding intervals of architectural void and solid, height and width. In another sense music and architecture are allied. They alone of all the arts are purely creative, since in them is presented, not a likeness of some known idea, but _a thing-in-itself_ brought to a distinct and complete expression of its nature. Neither a musical composition nor a work of architecture depends for its effectiveness upon resemblances to natural sounds in the one case, or to natural forms in the other. Of none of the other arts is this to such a degree true: they are not so much creative as re-creative, for in them all the artist takes his subject ready made from nature and presents it anew according to the dictates of his genius.